添加 isToday 类

[ghost]

可以开放个 is-today 类给用来设置今天的样式吗，下面加了几行，目测可行

initCalendar () {
...
const fullCol = Array.from(Array(weekRow * WEEK).keys())
        .map(i => {
          let value = firstDay <= i
            ? day++ % lastDate + 1
            : ''
          let date = new Date()  // +
          let isToday = date.getFullYear() == this.year && date.getMonth()+1 == this.month && value == date.getDate()  // +
          return {
            value,
            isToday,  // +
            active: false,
            isOtherMonth: firstDay > i || day > lastDate
          }
        })
      this.showDays = fullCol
...
}
classList (dayObj) {
      let oClassList = {
        'calendar__day--otherMonth': dayObj.isOtherMonth,
        'is-today': dayObj.isToday,  // +
        [this.prefixClass]: dayObj.active
      }

      if (dayObj.active) oClassList[dayObj.className] = true
      return oClassList
    },