(docs) Updated Readme status (#1038)

Changed status to Release candidate

Author: robindijkhof

README.md

@@ -5,7 +5,7 @@
 
 [![Build Status](https://travis-ci.org/angular/angularfire2.svg?branch=master)](https://travis-ci.org/angular/angularfire2) [![Join the chat at https://gitter.im/angular/angularfire2](https://badges.gitter.im/angular/angularfire2.svg)](https://gitter.im/angular/angularfire2?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
-Status: Beta
+Status: Release candidate
 
 ## What is AngularFire2?