Add GoReportCard badge

Author: heraclmene

README.md

@@ -2,6 +2,7 @@
 
 [![Build Status](https://travis-ci.org/bunsenapp/go-selenium.svg?branch=master)](https://travis-ci.org/bunsenapp/go-selenium)
 [![GoDoc](https://godoc.org/github.com/bunsenapp/go-selenium?status.svg)](https://godoc.org/github.com/bunsenapp/go-selenium)
+[![Go Report Card](https://goreportcard.com/badge/github.com/bunsenapp/go-selenium)](https://goreportcard.com/report/github.com/bunsenapp/go-selenium)
 
 ## Introduction