update oauth2 proxy link

Author: morbidick

README.md

@@ -2,7 +2,7 @@
 
 [![Build Status](https://travis-ci.org/morbidick/ansible-role-oauth2-proxy.svg?branch=master)](https://travis-ci.org/morbidick/ansible-role-oauth2-proxy)
 
-An ansible role to install and configure [oauth2 proxy](https://github.com/pusher/oauth2_proxy).
+An ansible role to install and configure [oauth2 proxy](https://github.com/oauth2-proxy/oauth2-proxy).
 
 ## Variables