Use svg instead of png to get better image quality

Author: PeterDaveHello

README.md

@@ -1,7 +1,7 @@
 [![browser support](https://ci.testling.com/darvin/github.png)](https://ci.testling.com/darvin/github)
 
 
-[![Build Status](https://travis-ci.org/darvin/github.png?branch=master)](https://travis-ci.org/darvin/github)
+[![Build Status](https://travis-ci.org/darvin/github.svg?branch=master)](https://travis-ci.org/darvin/github)
 
 [![Coverage Status](https://img.shields.io/coveralls/michael/github.svg)](https://coveralls.io/r/michael/github)