README: Coverage status badge upate, semver link

README.md

@@ -1,7 +1,7 @@
-semver for golang [![Build Status](https://drone.io/github.com/blang/semver/status.png)](https://drone.io/github.com/blang/semver/latest) [![GoDoc](https://godoc.org/github.com/blang/semver?status.png)](https://godoc.org/github.com/blang/semver) [![Coverage Status](https://coveralls.io/repos/blang/semver/badge.png)](https://coveralls.io/r/blang/semver)
+semver for golang [![Build Status](https://drone.io/github.com/blang/semver/status.png)](https://drone.io/github.com/blang/semver/latest) [![GoDoc](https://godoc.org/github.com/blang/semver?status.png)](https://godoc.org/github.com/blang/semver) [![Coverage Status](https://img.shields.io/coveralls/blang/semver.svg)](https://coveralls.io/r/blang/semver?branch=master)
 ======
 
-semver is a Semantic Versioning library written in golang. It fully covers spec version `2.0.0`.
+semver is a [Semantic Versioning](http://semver.org/) library written in golang. It fully covers spec version `2.0.0`.
 
 Usage
 -----