- [new] add `isCustomComponentElement` (#1832)
 - [fix] (<= v16.2) ensure that `this.state` starts out `null` when unspecified on a custom component (#1849)
 - [fix] `forwardRef`: respect `.displayName` on the forwardRef (#1817)
 - [deps] update `babel-preset-airbnb`, `chai`, `eslint`, `mocha`, `enzyme-adapter-utils`, `react-is`, `airbnb-js-shims`