Plugin weekOfYear doesn't work well for locale zh-cn

[DevinXian]

Issue code demo

const dayjs = require('dayjs')
const moment = require( 'moment')
require( 'dayjs/locale/zh-cn')
const weekOfYear = require('dayjs/plugin/weekOfYear')

moment.locale('zh-cn')

dayjs.locale('zh-cn')
dayjs.extend(weekOfYear)

console.log(dayjs('2019-08-18').week()) // 34
console.log(moment('2019-08-18').week()) // 33

Expected behavior

Both should be 33

Information

• Day.js Version [v1.8.15]
• Moment Version [v2.24.0]
• OS: [Mac OS X 10.14.4]
• Time zone: [GMT+08:00(China Standard Time)]

[PengJiyuan]

+1

[iamkun]

fixed in #658