message: [changelog] 2.0.7
diff: # Changelog
  +### [v2.0.7](https://github.com/youzan/vant/tree/v2.0.7)
  +`2019-07-11`
  +
  +**Improvements**
  +
  +- add CountDown component [\#3805](https://github.com/youzan/vant/pull/3805)
  +- Popup: add round prop [\#3781](https://github.com/youzan/vant/pull/3781)
  +- PullRefresh: add distance of slotProps [\#3829](https://github.com/youzan/vant/pull/3829)
  +- DropdownMenu: add close-on-click-outside prop [\#3824](https://github.com/youzan/vant/pull/3824)
  +- Swipe: add immediate option of swipeTo method [\#3821](https://github.com/youzan/vant/pull/3821)
  +- Slider: support number type of bar-height prop [\#3794](https://github.com/youzan/vant/pull/3794)
  +- IndexBar: add sticky-offset-top prop [\#3791](https://github.com/youzan/vant/pull/3791)
  +
  +**Bug Fixes**
  +
  +- fix Popup overlay may cover popup in some cases [\#3831](https://github.com/youzan/vant/pull/3831)
  +- fix Stepper add hack for iOS 12 page scroll [\#3804](https://github.com/youzan/vant/pull/3804)
  +- fix Dialog missing closeOnPopstate in type definition [\#3789](https://github.com/youzan/vant/pull/3789)
  +- fix DatetimePicker confirm event param incorrect when use filter [\#3816](https://github.com/youzan/vant/pull/3816)
  +
  +
  ### [v2.0.6](https://github.com/youzan/vant/tree/v2.0.6)
  `2019-07-05`
  