title: JSON value of type NSMutableArray cannot be converted to NSString
body: <h2>Description</h2>
  
  <p>I've just installed the module and implemented the sample example, in Android, it is working fine but I'm getting an issue on iOS. When I'm dismissing the error by clicking on Dismiss, it is working for me. I'm also attaching the sample code.
  i think it is an internal issue.</p>
  
  <h2>Expected Behavior</h2>
  
  <p>open calendar without getting this error.</p>
  
  <p>error message:</p>
  
  <pre><code>JSON value '(
          {
          label = increment;
          name = increment;
      },
          {
          label = decrement;
          name = decrement;
      }
  )' of type NSMutableArray cannot be converted to NSString
  
  +[RCTConvert NSString:]
      RCTConvert.m:56
  __49-[RCTComponentData createPropBlock:isShadowView:]_block_invoke.97
  __49-[RCTComponentData createPropBlock:isShadowView:]_block_invoke_2.98
  __49-[RCTComponentData propBlockForKey:isShadowView:]_block_invoke_2
  RCTPerformBlockWithLogFunction
  RCTPerformBlockWithLogPrefix
  __49-[RCTComponentData propBlockForKey:isShadowView:]_block_invoke
  __37-[RCTComponentData setProps:forView:]_block_invoke
  __NSDICTIONARY_IS_CALLING_OUT_TO_A_BLOCK__
  -[__NSDictionaryM enumerateKeysAndObjectsWithOptions:usingBlock:]
  -[RCTComponentData setProps:forView:]
  __50-[RCTUIManager createView:viewName:rootTag:props:]_block_invoke.405
  __44-[RCTUIManager flushUIBlocksWithCompletion:]_block_invoke
  __44-[RCTUIManager flushUIBlocksWithCompletion:]_block_invoke.461
  __RCTExecuteOnMainQueue_block_invoke
  _dispatch_call_block_and_release
  _dispatch_client_callout
  _dispatch_main_queue_callback_4CF
  __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
  __CFRunLoopRun
  CFRunLoopRunSpecific
  GSEventRunModal
  UIApplicationMain
  main
  start
  0x0
  
  </code></pre>
  
  <h2>Environment</h2>
  
  <ul>
  <li><code>react-native-calendars</code>: "^1.264.0"</li>
  <li><code>react-native</code>: "^0.58.5"</li>
  <li><code>react</code>: "16.8.6"</li>
  </ul>
  
  <h2>i think error is here in <code>accessibilityActions</code>:</h2>
  
  <p>path: ./node_modules/react-native-calendars/src/calendar/header/index.js.</p>
  
  <pre><code>import React, {Component} from 'react';
  import {ActivityIndicator, Platform} from 'react-native';
  import {View, Text, TouchableOpacity, Image} from 'react-native';
  import XDate from 'xdate';
  import PropTypes from 'prop-types';
  import styleConstructor from './style';
  import {weekDayNames} from '../../dateutils';
  import {CHANGE_MONTH_LEFT_ARROW, CHANGE_MONTH_RIGHT_ARROW} from '../../testIDs';
  
  
  class CalendarHeader extends Component {
    static displayName = 'IGNORE';
  
    static propTypes = {
      theme: PropTypes.object,
      hideArrows: PropTypes.bool,
      month: PropTypes.instanceOf(XDate),
      addMonth: PropTypes.func,
      showIndicator: PropTypes.bool,
      firstDay: PropTypes.number,
      renderArrow: PropTypes.func,
      hideDayNames: PropTypes.bool,
      weekNumbers: PropTypes.bool,
      onPressArrowLeft: PropTypes.func,
      onPressArrowRight: PropTypes.func,
      disableArrowLeft: PropTypes.bool,
      disableArrowRight: PropTypes.bool,
      webAriaLevel: PropTypes.number
    };
  
    static defaultProps = {
      monthFormat: 'MMMM yyyy',
      webAriaLevel: 1
    };
  
    constructor(props) {
      super(props);
      this.style = styleConstructor(props.theme);
      this.addMonth = this.addMonth.bind(this);
      this.substractMonth = this.substractMonth.bind(this);
      this.onPressLeft = this.onPressLeft.bind(this);
      this.onPressRight = this.onPressRight.bind(this);
    }
  
    addMonth() {
      this.props.addMonth(1);
    }
  
    substractMonth() {
      this.props.addMonth(-1);
    }
  
    shouldComponentUpdate(nextProps) {
      if (nextProps.month.toString('yyyy MM') !== this.props.month.toString('yyyy MM')) {
        return true;
      }
      if (nextProps.showIndicator !== this.props.showIndicator) {
        return true;
      }
      if (nextProps.hideDayNames !== this.props.hideDayNames) {
        return true;
      }
      if (nextProps.firstDay !== this.props.firstDay) {
        return true;
      }
      if (nextProps.weekNumbers !== this.props.weekNumbers) {
        return true;
      }
      if (nextProps.monthFormat !== this.props.monthFormat) {
        return true;
      }
      if (nextProps.renderArrow !== this.props.renderArrow) {
        return true;
      }
      if (nextProps.disableArrowLeft !== this.props.disableArrowLeft) {
        return true;
      }
      if (nextProps.disableArrowRight !== this.props.disableArrowRight) {
        return true;
      }
      return false;
    }
  
    onPressLeft() {
      const {onPressArrowLeft} = this.props;
      if (typeof onPressArrowLeft === 'function') {
        return onPressArrowLeft(this.substractMonth, this.props.month);
      }
      return this.substractMonth();
    }
  
    onPressRight() {
      const {onPressArrowRight} = this.props;
      if (typeof onPressArrowRight === 'function') {
        return onPressArrowRight(this.addMonth, this.props.month);
      }
      return this.addMonth();
    }
  
    render() {
      let leftArrow = &lt;View/&gt;;
      let rightArrow = &lt;View/&gt;;
      let weekDaysNames = weekDayNames(this.props.firstDay);
      const {testID} = this.props;
  
      if (!this.props.hideArrows) {
        leftArrow = (
          &lt;TouchableOpacity
            onPress={this.onPressLeft}
            disabled={this.props.disableArrowLeft}
            style={this.style.arrow}
            hitSlop={{left: 20, right: 20, top: 20, bottom: 20}}
            testID={testID ? `${CHANGE_MONTH_LEFT_ARROW}-${testID}`: CHANGE_MONTH_LEFT_ARROW}
          &gt;
            {this.props.renderArrow
              ? this.props.renderArrow('left')
              : &lt;Image
                source={require('../img/previous.png')}
                style={this.props.disableArrowLeft ? this.style.disabledArrowImage : this.style.arrowImage}
              /&gt;}
          &lt;/TouchableOpacity&gt;
        );
        rightArrow = (
          &lt;TouchableOpacity
            onPress={this.onPressRight}
            disabled={this.props.disableArrowRight}
            style={this.style.arrow}
            hitSlop={{left: 20, right: 20, top: 20, bottom: 20}}
            testID={testID ? `${CHANGE_MONTH_RIGHT_ARROW}-${testID}`: CHANGE_MONTH_RIGHT_ARROW}
          &gt;
            {this.props.renderArrow
              ? this.props.renderArrow('right')
              : &lt;Image
                source={require('../img/next.png')}
                style={this.props.disableArrowRight ? this.style.disabledArrowImage : this.style.arrowImage}
              /&gt;}
          &lt;/TouchableOpacity&gt;
        );
      }
  
      let indicator;
      if (this.props.showIndicator) {
        indicator = &lt;ActivityIndicator color={this.props.theme &amp;&amp; this.props.theme.indicatorColor}/&gt;;
      }
  
      const webProps = Platform.OS === 'web' ? {'aria-level': this.props.webAriaLevel} : {};
  
      return (
        &lt;View
          style={this.props.style}
          accessible
          accessibilityRole={'adjustable'}
          accessibilityActions={[
            {name: 'increment', label: 'increment'},
            {name: 'decrement', label: 'decrement'}
          ]}
          onAccessibilityAction={this.onAccessibilityAction}
          accessibilityElementsHidden={this.props.accessibilityElementsHidden} // iOS
          importantForAccessibility={this.props.importantForAccessibility} // Android
        &gt;
          &lt;View style={this.style.header}&gt;
            {leftArrow}
            &lt;View style={{flexDirection: 'row'}}&gt;
              &lt;Text
                allowFontScaling={false}
                style={this.style.monthText}
                {...webProps}
              &gt;
                {this.props.month.toString(this.props.monthFormat)}
              &lt;/Text&gt;
              {indicator}
            &lt;/View&gt;
            {rightArrow}
          &lt;/View&gt;
          {!this.props.hideDayNames &amp;&amp;
            &lt;View style={this.style.week}&gt;
              {this.props.weekNumbers &amp;&amp;
                &lt;Text allowFontScaling={false} style={this.style.dayHeader}&gt;&lt;/Text&gt;
              }
              {weekDaysNames.map((day, idx) =&gt; (
                &lt;Text
                  allowFontScaling={false}
                  key={idx}
                  style={this.style.dayHeader}
                  numberOfLines={1}
                  accessibilityLabel={''}
                  // accessible={false} // not working
                  // importantForAccessibility='no'
                &gt;
                  {day}
                &lt;/Text&gt;
              ))}
            &lt;/View&gt;
          }
        &lt;/View&gt;
      );
    }
  
    onAccessibilityAction = event =&gt; {
      switch (event.nativeEvent.actionName) {
      case 'decrement':
        this.onPressLeft();
        break;
      case 'increment':
        this.onPressRight();
        break;
      default:
        break;
      }
    }
  }
  
  export default CalendarHeader;
  </code></pre>