chore(release): 2.3.1 [skip ci]

<a name="2.3.1"></a>
## [2.3.1](reactjs/react-transition-group@v2.3.0...v2.3.1) (2018-04-14)

### Bug Fixes

* **deps:** Move loose-envify and semantic-release to devDependencies ([reactjs#319](reactjs#319)) ([b4ec774](reactjs@b4ec774))