GitHub: Added Discord link to New Issue (#14802)

Author: 0x5bfa

.github/ISSUE_TEMPLATE/config.yml

@@ -3,3 +3,6 @@ contact_links:
   - name: Translation issue
     url: https://crowdin.com/project/files-app
     about: Help improve translations on Crowdin.
+  - name: Question & Discussion
+    url: https://discord.gg/files
+    about: Post your questions and join the discussion. You can participate in chats on every channel.