chore: Add @feaber to contributors

Author: bebraw

CONTRIBUTORS.md

@@ -1,3 +1,4 @@
-* [Vladimir Kutepov](https://github.com/frenzzy) - Added `autoFocus` to <select>. #1
+* [Vladimir Kutepov](https://github.com/frenzzy) - Add `autoFocus` to <select>. #1
 * [José Diaz Seng](https://github.com/joseds) - React 15.5 upgrade, fixed deprecations. #2
 * [Artem Sapegin](https://github.com/sapegin) - Support React 16. #3
+* [feaber](https://github.com/feaber) - Fix `onBlur` behavior on Firefox. #4