title: Invalid prop `children` supplied to `DropdownItem` expected a ReactNode
body: <ul>
  <li>components: <code>DropdownItem</code></li>
  <li>reactstrap version <code>^8.0.0</code></li>
  <li>react version <code>^16.8.6</code></li>
  <li>bootstrap version <code>^4.3.1</code></li>
  </ul>
  
  <p>I am using reactstrap dropdown. And I am trying to populate the dropdown items using a map function</p>
  
  <pre><code>render() {
      return (
          &lt;Dropdown isOpen={this.state.open} toggle={this.toggle}&gt;
          &lt;DropdownToggle caret&gt;
              {this.props.name}
          &lt;/DropdownToggle&gt;
          &lt;DropdownMenu&gt;
              {this.props.items.map(function(item) {
                  return(
                      &lt;DropdownItem key={item}&gt;
                          &lt;text&gt;{item}&lt;/text&gt;
                      &lt;/DropdownItem&gt;
                  );
              })}
          &lt;/DropdownMenu&gt;
      &lt;/Dropdown&gt;
      );
  }
  </code></pre>
  
  <p>If I do not wrap the {item} inside a tag(div or text) I get the following error while running test case.</p>
  
  <pre><code>console.error node_modules/prop-types/checkPropTypes.js:20
  Warning: Failed prop type: Invalid prop children supplied to DropdownItem, expected a ReactNode.
  in DropdownItem
  </code></pre>
  
  <p>Just curious to know why am I getting the warning if I do not wrap it in a tag?</p>