Fix avatar URL

Author: rkoenig-openai

authors.yaml

@@ -411,7 +411,7 @@ phundal-openai:
 rkoenig-openai:
   name: "Robin Koenig"
   website: "https://www.linkedin.com/in/robinkoenig/"
-  avatar: "https://media.licdn.com/dms/image/v2/C5603AQEqUVtbts8Huw/profile-displayphoto-shrink_400_400/profile-displayphoto-shrink_400_400/0/1558137883581?e=1753920000&v=beta&t=jcm-qNJfmgVJsS6uNHxHu5T2nQoUWkXivthzxTJMWqA"
+  avatar: "https://avatars.githubusercontent.com/u/208886811?v=4"
 
 joshbickett:
   name: "Josh Bickett"