fix: replace rughh default discord link with an indefinite one

Author: Makisai

config/whitelabel.yml

@@ -8,8 +8,8 @@
   recurring: second wednesday
   email: hamburg@onruby.de
   twitter: HamburgOnRuby
-  discord: https://discord.gg/xCCcnbGR
   bluesky: hamburgonruby
+  discord: https://discord.gg/qFg49HcJ2a
   github_org: rughh
   github_repo: planning
   github_issue_template: 'meetup.md'