Add Slack link to issue template (#2282)

Author: bpmct

.github/ISSUE_TEMPLATE/config.yml

@@ -2,4 +2,7 @@ blank_issues_enabled: false
 contact_links:
   - name: Question
     url: https://github.com/cdr/code-server/discussions/new?category_id=22503114
-    about: Ask the community for help
+    about: Ask the community for help on our GitHub Discussions board
+  - name: Chat
+    about: Need immediate help or just want to talk? Hop in our Slack
+    url: https://cdr.co/join-community