update youtube-admins slack user group

Author: Priyankasaggu11929

communication/slack-config/usergroups.yaml

@@ -86,7 +86,7 @@ usergroups:
       - pnbrown
       - CIPHERTron
       - chadmcrowell
-      - Hii-Arpit
+      - hii-arpit
       - kaslin
 
   - name: zoom-admins