github: redirect to Libera webchat for questions

Author: emersion

.github/ISSUE_TEMPLATE/config.yml

@@ -1,5 +1,5 @@
 blank_issues_enabled: false
 contact_links:
   - name: Question
-    url: "https://libera.chat/"
+    url: "https://web.libera.chat/gamja/#emersion"
     about: "Please ask questions in #emersion on Libera Chat"