better agent skills URL

Author: freyfogle

README.md

@@ -27,7 +27,7 @@ You can find [a comprehensive tutorial for using this module on the OpenCage sit
 
 ## Working with AI / Agent Skill
 
-There is an [Agent Skill for working with the OpenCage Geocoding API](https://github.com/OpenCageData/opencage-skills/blob/master/opencage-geocoding-api/SKILL.md) which includes a reference file for developing in PHP using this library.
+There is an [Agent Skill for working with the OpenCage Geocoding API](https://github.com/OpenCageData/opencage-skills/) which includes a reference file for developing in PHP using this library.
 
 
 ## Installation