Update README.md

update coverage badge

Author: Dean Karn

README.md

@@ -2,7 +2,7 @@
 <img align="right" src="https://raw.githubusercontent.com/go-playground/universal-translator/master/logo.png">
 ![Project status](https://img.shields.io/badge/version-0.10.0-green.svg)
 [![Build Status](https://semaphoreci.com/api/v1/joeybloggs/universal-translator/branches/master/badge.svg)](https://semaphoreci.com/joeybloggs/universal-translator)
-[![Coverage Status](https://coveralls.io/repos/github/go-playground/universal-translator/badge.svg?branch=master)](https://coveralls.io/github/go-playground/universal-translator?branch=master)
+[![Coverage Status](https://coveralls.io/repos/github/go-playground/universal-translator/badge.svg)](https://coveralls.io/github/go-playground/universal-translator)
 [![Go Report Card](https://goreportcard.com/badge/github.com/go-playground/universal-translator)](https://goreportcard.com/report/github.com/go-playground/universal-translator)
 [![GoDoc](https://godoc.org/github.com/go-playground/universal-translator?status.svg)](https://godoc.org/github.com/go-playground/universal-translator)
 ![License](https://img.shields.io/dub/l/vibe-d.svg)