ToObject

ToObject 添加 `.toObject()` API 以返回带有日期属性的 `object`。

var toObject = require('dayjs/plugin/toObject')
dayjs.extend(toObject)

dayjs('2019-01-25').toObject()
/* { years: 2019,
     months: 0,
     date: 25,
     hours: 0,
     minutes: 0,
     seconds: 0,
     milliseconds: 0 } */