message: [changelog] 1.6.16
diff: ## Changelog
  +## [v1.6.16](https://github.com/youzan/vant/tree/v1.6.16)
  +`2019-04-26`
  +
  +**Improvements**
  +
  +- Step: add active-icon slot [\#3193](https://github.com/youzan/vant/pull/3193)
  +- NumberKeyboard: add title-left slot [\#3194](https://github.com/youzan/vant/pull/3194)
  +- Icon: update new icon & hot icon [\#3203](https://github.com/youzan/vant/pull/3203)
  +
  +**Bug Fixes**
  +
  +- fix Row align bottom not work [\#3209](https://github.com/youzan/vant/pull/3209)
  +- fix Area change event values incorrect [\#3219](https://github.com/youzan/vant/pull/3219)
  +- fix Field add hack for iOS 12 scroll position [\#3204](https://github.com/youzan/vant/pull/3204)
  +- fix AddressList not trigger select event when click radio icon [\#3214](https://github.com/youzan/vant/pull/3214)
  +- fix ContactList not trigger select event when click radio icon [\#3218](https://github.com/youzan/vant/pull/3218)
  +- fix Slider drag and `value` props change at the same time can not drag success [\#3206](https://github.com/youzan/vant/pull/3206)
  +
  +
  ## [v1.6.15](https://github.com/youzan/vant/tree/v1.6.15)
  `2019-04-19`
  