message: [changelog] 1.5.2
diff: ## Changelog
  +## [v1.5.2](https://github.com/youzan/vant/tree/v1.5.2)
  +`2019-01-10`
  +
  +**Improvements**
  +
  +- Icon: add cart-circle icon [\#2480](https://github.com/youzan/vant/pull/2480)
  +- Color: update base green to wechat green [\#2479](https://github.com/youzan/vant/pull/2479)
  +- Coupon: add description prop [\#2458](https://github.com/youzan/vant/pull/2458)
  +- ImagePreview: add className prop [\#2433](https://github.com/youzan/vant/pull/2433)
  +- Sku: support hide soldout sku [\#2472](https://github.com/youzan/vant/pull/2472)
  +
  +**Bug Fixes**
  +
  +- fix DatetimePicker value observable [\#2427](https://github.com/youzan/vant/pull/2427)
  +- fix Icon rounded lines [\#2437](https://github.com/youzan/vant/pull/2437)
  +- fix SubmitBar can not hide price [\#2469](https://github.com/youzan/vant/pull/2469)
  +- fix Swipe position wrong when use swipeTo [\#2471](https://github.com/youzan/vant/pull/2471)
  +- fix Stepper wrong value when input is empty and min is zero [\#2470](https://github.com/youzan/vant/pull/2470)
  +- fix Tab should not have line animation when inited [\#2459](https://github.com/youzan/vant/pull/2459)
  +
  +
  ## [v1.5.1](https://github.com/youzan/vant/tree/v1.5.1)
  `2019-01-01`
  