docs(readme): add clarity on angular requirement

* add note strongly recommending the use of Angular 1.3.18 or higher for UI
  Bootstrap 0.13.3 and higher due to animation fixes.

Closes #4277
Closes #4278

Author: icfantv

Diff for: README.md

@@ -30,6 +30,8 @@ Do you want to see directives in action? Visit http://angular-ui.github.io/boots
 Installation is easy as UI Bootstrap has minimal dependencies - only the AngularJS and Twitter Bootstrap's CSS are required.
 Note: Since version 0.13.0, UI Bootstrap depends on [ngAnimate](https://docs.angularjs.org/api/ngAnimate) for transitions and animations, such as the accordion, carousel, etc. Include `ngAnimate` in the module dependencies for your app in order to enable animation.
 
+Additionally, it is srongly recommended that for UI Bootstrap 0.13.3 and higher you use Angular 1.3.18 or higher due to animation fixes. 
+
 #### Install with NPM
 
 ```sh