Fix typo in README.md

Author: zignd

README.md

@@ -1,6 +1,6 @@
 # errors [![GoDoc](https://godoc.org/github.com/zignd/errors?status.svg)](https://godoc.org/github.com/zignd/errors) [![Report card](https://goreportcard.com/badge/github.com/zignd/errors)](https://goreportcard.com/report/github.com/zignd/errors)     
 
-An errors package that will help you handle them gracefully. It allows you to add contextual information to your errors, to wrap them and they even get a stack trace. Inspired by the [github.com/pgk/errors](https://www.github.com/pgk/errors) package and Node.js' [verror](https://github.com/joyent/node-verror) module.
+An errors package that will help you handle them gracefully. It allows you to add contextual information to your errors, to wrap them and they even get a stack trace. Inspired by the [github.com/pkg/errors](https://www.github.com/pkg/errors) package and Node.js' [verror](https://github.com/joyent/node-verror) module.
 
 # Features