message: [changelog] 1.0.8
diff: ## Changelog
  +### [1.0.8](https://github.com/youzan/vant/tree/v1.0.8)
  +`2018-04-20`
  +
  +**Improvements**
  +- add git hook, optimize dev process [\#883](https://github.com/youzan/vant/pull/883) [@jerryni](https://github.com/jerryni)
  +
  +**Bug Fixes**
  +- Cell: optimize left icon [\#893](https://github.com/youzan/vant/pull/893) [@chenjiahan](https://github.com/chenjiahan)
  +- Build: should use babel sync compile [\#885](https://github.com/youzan/vant/pull/885) [@chenjiahan](https://github.com/chenjiahan)
  +- Field: allow negative number when type is number [\#889](https://github.com/youzan/vant/pull/889) [@chenjiahan](https://github.com/chenjiahan)
  +- Popup: fix lock scroll [\#891](https://github.com/youzan/vant/pull/891) [@Tinysymphony](https://github.com/Tinysymphony)
  +
  +
  ### [1.0.7](https://github.com/youzan/vant/tree/v1.0.7)
  `2018-04-17`
  