message: docs(changelog): 2.4.2-beta.1
diff: # Changelog
  +### [v2.4.2-beta.1](https://github.com/youzan/vant/compare/v2.4.2-beta.0...v2.4.2-beta.1)
  +`2020-01-09`
  +
  +**Feature**
  +
  +* Field: add digit type [#5524](https://github.com/youzan/vant/issues/5524)
  +* Sku: add properties support [#5525](https://github.com/youzan/vant/issues/5525)
  +* Calendar: scroll to current month when show [#5526](https://github.com/youzan/vant/issues/5526)
  +
  +**Bug Fixes**
  +
  +* CouponList: incorrect click feedback [#5521](https://github.com/youzan/vant/issues/5521)
  +* Field: should limit number input in iOS [#5520](https://github.com/youzan/vant/issues/5520)
  +* Tabs: can not render line when wrapper is fixed [#5496](https://github.com/youzan/vant/issues/5496)
  +
  +**Improvement**
  +
  +* CouponList: update style [#5501](https://github.com/youzan/vant/issues/5501)
  +* AddressList: update style [#5507](https://github.com/youzan/vant/issues/5507)
  +
  +
  ### [v2.4.2-beta.0](https://github.com/youzan/vant/compare/v2.4.1...v2.4.2-beta.0)
  `2020-01-06`
  