title: Invalid February date using moment.js
body: <p>I'm using moment.js to format my selected date. When I've selected a February date, moment.js has returned 'invalid date':</p>
  
  <pre><code>moment('28/02/2018').isValid(); //returns false
  </code></pre>
  
  <p>But, when I've selected a March date, moment.js has returned a valid date:</p>
  
  <pre><code>moment('01/03/2018').isValid(); //returns true
  </code></pre>
  
  <p>Can someone say me what I'm doing wrong?</p>