docs(README.md): add link to Angular 2 repo

Might be helpful for those completely new to Angular in general, that intended to view the upcoming
2.0 version.

Closes #14532

Author: MarkPieszak

README.md

@@ -19,6 +19,7 @@ piece of cake. Best of all? It makes development fun!
 * Contribution guidelines: [CONTRIBUTING.md](https://github.com/angular/angular.js/blob/master/CONTRIBUTING.md)
 * Dashboard: https://dashboard.angularjs.org
 
+##### Looking for Angular 2 (beta)? Go here: https://github.com/angular/angular
 
 Building AngularJS
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