chore: Add codeclimate badge

Author: cwill747

README.md

@@ -1,6 +1,7 @@
 # angular-libphonenumber - [AngularJS](http://angularjs.org/) input masks for phone numbers
 [![Build Status](https://travis-ci.org/cwill747/angular-libphonenumber.svg)](https://travis-ci.org/cwill747/angular-libphonenumber)
 [![Coverage Status](https://coveralls.io/repos/cwill747/angular-libphonenumber/badge.svg?branch=master)](https://coveralls.io/r/cwill747/angular-libphonenumber?branch=master)
+[![Code Climate](https://codeclimate.com/github/cwill747/angular-libphonenumber/badges/gpa.svg)](https://codeclimate.com/github/cwill747/angular-libphonenumber)
 ## Description
 angular-libphonenumber is an angular directive that can be used as an input mask.
 By default, all numbers are formatted in US format, but the format can be set with