title: Vuetify.js and date-picker watch doesn't trigger on month
body: <p>Running <code>Vue.js</code> and <code>Vuetify.js</code>.</p>
  
  <p>I'm testing the <code>data-picker</code> and the <code>watch</code> method for triggering events on change of month. However, it only seems <code>watch</code> is noticing change of <code>year</code>, and not <code>month</code>.</p>
  
  <p>HTML</p>
  
  <pre><code>&lt;div id="app"&gt;
    &lt;v-app&gt;
  
      &lt;v-date-picker ref="picker" v-model="date" :picker-date.sync="pickerDate" type="month"&gt;&lt;/v-date-picker&gt;
  
    &lt;/v-app&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>JS:</p>
  
  <pre><code>new Vue({
    el: "#app",
    data() {
      return {
        pickerDate: null,
        date: null,
      };
    },
    watch: {
      pickerDate(val) {
        console.log(val)
      }
    }
  });
  </code></pre>
  
  <p>Codepen example shown here: <a href="https://codepen.io/alfredballe84/pen/varGWe?editors=1111" rel="nofollow noreferrer">https://codepen.io/alfredballe84/pen/varGWe?editors=1111</a></p>