message: [changelog] 0.12.7
diff: ## Changelog
  +### [0.12.7](https://github.com/youzan/vant/tree/v0.12.7)
  +`2018-01-31`
  +
  +**Improvements**
  +* Area: add item-height & visible-item-count props [\#591](https://github.com/youzan/vant/pull/591) [@chenjiahan](https://github.com/chenjiahan)
  +* Dialog: support component call [\#593](https://github.com/youzan/vant/pull/593) [@chenjiahan](https://github.com/chenjiahan)
  +* Toast: support multiple instance [\#586](https://github.com/youzan/vant/pull/586) [@chenjiahan](https://github.com/chenjiahan)
  +* Sku: add getSkuData method [\#585](https://github.com/youzan/vant/pull/585) [@chenjiahan](https://github.com/chenjiahan)
  +
  +**Bug Fixes**
  +* fix Field multi line label style error [\#583](https://github.com/youzan/vant/pull/583) [@chenjiahan](https://github.com/chenjiahan)
  +
  ### [0.12.6](https://github.com/youzan/vant/tree/v0.12.6)
  `2018-01-25`
  