message: docs(changelog): 2.3.1
diff: # Changelog
  +### [v2.3.1](https://github.com/youzan/vant/tree/v2.3.1)
  +`2019-12-20`
  +
  +**Bug Fixes**
  +
  +- Fix uncompiled ES6 code in the entry file
  +
  +
  ### [v2.3.0](https://github.com/youzan/vant/tree/v2.3.0)
  `2019-12-20`
  