Update FUNDING.yml

Author: tomkralidis

.github/FUNDING.yml

@@ -1,4 +1,4 @@
 # These are supported funding model platforms
 
 #github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
-custom: ['https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=GBTEECH2NB3GC&source=url'] # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
+custom: ['https://github.com/geopython/pycsw/wiki/Sponsorship'] # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']