docs: svg travis badge

Author: epoberezkin

Readme.md

@@ -1,6 +1,6 @@
 # json-pointer
 
-[![Build Status](https://travis-ci.org/manuelstofer/json-pointer.png?branch=master)](https://travis-ci.org/manuelstofer/json-pointer)
+[![Build Status](https://travis-ci.org/manuelstofer/json-pointer.svg?branch=master)](https://travis-ci.org/manuelstofer/json-pointer)
 [![npm version](https://badge.fury.io/js/json-pointer.svg)](https://www.npmjs.com/package/json-pointer)
 [![Coverage Status](https://coveralls.io/repos/github/manuelstofer/json-pointer/badge.svg?branch=master&service=github)](https://coveralls.io/github/manuelstofer/json-pointer?branch=master)