title: Contact Form 7 datepicker - date format not working for other language than english
body: <p>I have the Contact Form Datepicker plugin installed (version 2.6.0) and a simple contact form like this:</p>
  
  <pre><code>[date date-508 id:date-508 date-format:dd.mm.yy]
  </code></pre>
  
  <p>Date format dd.mm.yy is showing correctly only in english.</p>
  
  <p>Once I change the page to any other language it displays like: dd/mm/yy:
  01/11/2018</p>
  
  <p>I have WPML 4.0.8.
  The datepicker window is translated to other languages but the format of selected date is wrong. </p>
  
  <p>Any idea how to debug this? 
  What's causing this behavior?</p>
  
  <p>Thanks</p>