title: can't add header info properly using jstoXML
body: <p>I am trying to convert my table into xml. currently, I have two rows.  But I can not add the header information properly using jsToXml.Here is my code.</p>
  <pre><code>import { toXML } from 'jstoxml';
  
  export class NgbdModalComponentModule {
        constructor() {
          const table = [
            {
              row: 'bar'
            },
            {
              row: 'bar2'
            }
          ];
          const xmlOptions = {
            header: '&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-16&quot; standalone=&quot;yes&quot;?&gt;',
            indent: ' '
          };
      
          console.log(toXML(table, xmlOptions));
        }
      }
  </code></pre>
  <p>and output is look like that:</p>
  <pre><code>&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-16&quot; standalone=&quot;yes&quot;?&gt;
  &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-16&quot; standalone=&quot;yes&quot;?&gt;
  &lt;row&gt;bar&lt;/row&gt;
  &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-16&quot; standalone=&quot;yes&quot;?&gt;
  &lt;row&gt;bar2&lt;/row&gt;
  </code></pre>
  <p>But Output should be like that:</p>
  <pre><code>&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-16&quot; standalone=&quot;yes&quot;?&gt;
  &lt;row&gt;bar&lt;/row&gt;
  &lt;row&gt;bar2&lt;/row&gt;
  </code></pre>
  <p>I have also created a <a href="https://stackblitz.com/edit/angular-nf8k31-uyjdob?file=app/modal-component.module.ts" rel="nofollow noreferrer">stackblitz</a>.</p>