[README.md] fix broken Add-on rules link

Author: anxdpanic

README.md

@@ -8,7 +8,7 @@ This branch is not used for public. Please use one of the other branches availab
 
 ## Quick Kodi development links
 
-* [Add-on rules](https://github.com/xbmc/xbmc/blob/master/CONTRIBUTING.md)
+* [Add-on rules](https://github.com/xbmc/repo-scripts/blob/master/CONTRIBUTING.md)
 * [Submitting an add-on details](http://kodi.wiki/view/Submitting_Add-ons)
 * [Code guidelines](http://kodi.wiki/view/Official:Code_guidelines_and_formatting_conventions)
 * [Kodi development](http://kodi.wiki/view/Development)