chore: remove unused funding links

Author: d-biehl

.github/FUNDING.yml

@@ -10,4 +10,4 @@ open_collective: robotcode # Replace with a single Open Collective username
 # issuehunt: # Replace with a single IssueHunt username
 # otechie: # Replace with a single Otechie username
 # lfx_crowdfunding: # Replace with a single LFX Crowdfunding project-name e.g., cloud-foundry
-custom: ['https://www.buymeacoffee.com/dbiehl', 'https://paypal.me/dbiehl74'] # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
+# custom: [] # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']