title: Default time value through v-model not updating on vue2-datepicker
body: <p>I am using vue2-datepicker</p>
  <pre><code>    &lt;date-picker
          type=&quot;time&quot; id=&quot;start&quot;
          :time-picker-options=&quot;startTimeOptions&quot;
          v-model=&quot;start&quot;
          value-type=&quot;time&quot;
          format=&quot;hh:mm A&quot;
      &gt;&lt;/date-picker&gt;
  </code></pre>
  <p>and here's the start and startTimeOptions :</p>
  <pre><code>startTimeOptions:{start: '00:00',step: '00:15',end: '23:45',format: 'hh:mm A'},
  start:'12:00' //(also tried with start:'12:00 AM' &amp; start:{hh:'12',mm:'00',A : 'AM'})
  </code></pre>
  <p>But none of the above helps to update the value.
  At the same time after selecting time on the input, I could see the below value.
  <a href="https://i.stack.imgur.com/DhXTX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DhXTX.png" alt="enter image description here" /></a></p>