Merge pull request #21 from Stebalien/fix-readme

Fix the coverage badge in the README

README.md

@@ -4,7 +4,7 @@ go-ipld-format
 [![](https://img.shields.io/badge/made%20by-Protocol%20Labs-blue.svg?style=flat-square)](http://ipn.io)
 [![](https://img.shields.io/badge/project-IPFS-blue.svg?style=flat-square)](http://ipfs.io/)
 [![](https://img.shields.io/badge/freenode-%23ipfs-blue.svg?style=flat-square)](http://webchat.freenode.net/?channels=%23ipfs)
-[![Coverage Status](https://coveralls.io/repos/github/ipfs/go-ipld-format/badge.svg?branch=master)](https://coveralls.io/github/ipfs/go-ipld-format?branch=master)
+[![Coverage Status](https://codecov.io/gh/ipfs/go-ipld-format/branch/master/graph/badge.svg)](https://codecov.io/gh/ipfs/go-ipld-format/branch/master)
 [![Travis CI](https://travis-ci.org/ipfs/go-ipld-format.svg?branch=master)](https://travis-ci.org/ipfs/go-ipld-format)
 
 > go-ipld-format is a set of interfaces that a type needs to implement in order to be a part of the ipld merkle-forest.