updating required angular version

Author: jonshaffer

README.md

@@ -2,7 +2,7 @@
 
 `angular-data-table` is a AngularJS directive for presenting large and complex data.  It has all the features you would expect from any other table but in a light package with _no external depedencies_. The table was designed to be extremely flexible and light; it doesn't make any assumptions about your data or how you: filter, sort or page it.
 
-It was engineered from its conception to handle thousands of rows without sacrificing performance.  It was built for modern browsers using _ES6, CSS3 and HTML5_ and only supports [Evergreen Browsers](http://eisenbergeffect.bluespire.com/evergreen-browsers/) and >= 1.4.x Angular.
+It was engineered from its conception to handle thousands of rows without sacrificing performance.  It was built for modern browsers using _ES6, CSS3 and HTML5_ and only supports [Evergreen Browsers](http://eisenbergeffect.bluespire.com/evergreen-browsers/) and >= 1.5.x Angular.
 
 Sadly, this project is **not Angular2 upgrade compatible**. Fortunately, we have authored [angular2-data-table](https://github.com/swimlane/angular2-data-table) which is the successor to this project. **We are going to slowly be transitioning this project maintenance mode**. We will continue to provide feedback to the community and accept PRs but we won't be doing any major new development.