fix(VCalendar): forward all bound events to internal elements

[KaelWD]

Markup:

<template>
  <div>
    <v-sheet height="300">
      <v-chip
        draggable
        color="blue"
      >drag me over the calendar</v-chip> mouseUp and mouseEnter functions no longer work with the dragged element
      <v-calendar
        ref="calendar"
        type="month"
        start="2021-01-17"
        :weekdays="[1, 2, 3, 4, 5, 6, 0]"
        @dragover:day="dragoverDay"
        @mouseenter:day="mouseenterDay"
        @mouseup:day="mouseupDay"
      ></v-calendar>
    </v-sheet>
  </div>
</template>

<script>
  export default {
    data: () => ({
    }),
    methods: {
      dragoverDay (event) {
        console.log('dragover', event.day)
      },
      mouseenterDay (event) {
        console.log('enter', event.day)
      },
      mouseupDay (event) {
        console.log('up', event.day)
      },
    },
  }
</script>