docs(readme): fix small typo in README.md (angular#441)

Remove word 'add' from "Updating to a newer version of the Quickstart Repo"
section of GitHub README.

Author: pixelchutes

README.md

@@ -14,7 +14,7 @@ Please keep that in mind before posting issues and PRs.
 
 ## Updating to a newer version of the Quickstart Repo
 
-From time to time the QuickStart will add be enhanced with support for new features or to reflect
+From time to time the QuickStart will be enhanced with support for new features or to reflect
 changes to the [official Style Guide](https://angular.io/docs/ts/latest/guide/style-guide.html).
 
 You can update your existing project to an up-to-date QuickStart by following these instructions: