chore: add github-sponsor

Author: rahuldkjain

.github/FUNDING.yml

@@ -1,6 +1,6 @@
 # These are supported funding model platforms
 
-github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
+github: rahuldkjain
 patreon: # Replace with a single Patreon username
 open_collective: github-profile-readme-generator
 ko_fi: rahuldkjain
@@ -9,5 +9,4 @@ community_bridge: # Replace with a single Community Bridge project-name e.g., cl
 liberapay: # Replace with a single Liberapay username
 issuehunt: # Replace with a single IssueHunt username
 otechie: # Replace with a single Otechie username
-custom:
-  ["https://paypal.me/rahuldkjain", "https://www.buymeacoffee.com/rahuldkjain"]
+custom: ['https://paypal.me/rahuldkjain', 'https://www.buymeacoffee.com/rahuldkjain']