Update React badge in README for React 16 (#122)

Author: paulyoung

README.md

@@ -2,7 +2,7 @@
 
 [![Maintainer: ethul](https://img.shields.io/badge/maintainer-ethul-lightgrey.svg)](http://github.com/ethul)
 [![Maintainer: paf31](https://img.shields.io/badge/maintainer-paf31-lightgrey.svg)](http://github.com/paf31)
-![React: 0.15](https://img.shields.io/badge/react-0.15-lightgrey.svg)
+![React: 16](https://img.shields.io/badge/react-16-lightgrey.svg)
 
 Low-level React Bindings for PureScript.