Update README.md

Author: Dean Karn

README.md

@@ -1,6 +1,6 @@
 Package errors
 ============
-![Project status](https://img.shields.io/badge/version-2.0.0-green.svg)
+![Project status](https://img.shields.io/badge/version-3.0.0-green.svg)
 [![Build Status](https://semaphoreci.com/api/v1/joeybloggs/errors/branches/master/badge.svg)](https://semaphoreci.com/joeybloggs/errors)
 [![Go Report Card](https://goreportcard.com/badge/github.com/go-playground/errors)](https://goreportcard.com/report/github.com/go-playground/errors)
 [![GoDoc](https://godoc.org/github.com/go-playground/errors?status.svg)](https://godoc.org/github.com/go-playground/errors)