Update README.md

Author: ichiriac

README.md

@@ -1,7 +1,7 @@
 <h1 align="center">php-parser</h1>
 <p align="center">
 <a href="https://travis-ci.org/glayzzle/php-parser"><img src="https://travis-ci.org/glayzzle/php-parser.svg"></a>
-<a href="https://coveralls.io/r/glayzzle/php-parser"><img src="https://img.shields.io/coveralls/glayzzle/php-parser.svg"></a>
+<a href='https://coveralls.io/github/glayzzle/php-parser?branch=master'><img src='https://coveralls.io/repos/github/glayzzle/php-parser/badge.svg?branch=master' alt='Coverage Status' /></a>
 <a title="npm version" href="https://www.npmjs.com/package/php-parser"><img src="https://badge.fury.io/js/php-parser.svg"></a>
 <a title="npm downloads" href="https://www.npmjs.com/package/php-parser"><img src="https://img.shields.io/npm/dm/php-parser.svg?style=flat"></a>
 <a title="Gitter" href="https://gitter.im/glayzzle/Lobby"><img src="https://img.shields.io/badge/GITTER-join%20chat-green.svg"></a>