el-data-pick：根据接口返回参数，限制日期选择范围

this.$http.get(url).then((res)=> {
                    // this.currentBillingCycle 为返回的日期（年月，eg：201911）
                    let year = this.currentBillingCycle.slice(0,4);
                    let month = this.currentBillingCycle.slice(4,6);
                    this.currentDate = year + '-' + month + '-' + '01'
                });

data（）{
      return{
             pickerOptions: {
                    disabledDate: (time) => {
                        let d = new Date(this.currentDate)
                        return time.getTime() > d
                    }
             }
      }
}