remove code climate badge from readme.

Author: diasbruno

Diff for: README.md

@@ -3,7 +3,6 @@
 Accessible modal dialog component for React.JS
 
 [![Build Status](https://travis-ci.org/reactjs/react-modal.svg?branch=v1)](https://travis-ci.org/reactjs/react-modal)
-[![Code Climate](https://codeclimate.com/github/reactjs/react-modal/badges/gpa.svg)](https://codeclimate.com/github/reactjs/react-modal)
 [![Coverage Status](https://coveralls.io/repos/github/reactjs/react-modal/badge.svg?branch=master)](https://coveralls.io/github/reactjs/react-modal?branch=master)
 ![gzip size](http://img.badgesize.io/https://unpkg.com/react-modal/dist/react-modal.min.js?compression=gzip)