docs: update issue template w/ link to discussions

.github/ISSUE_TEMPLATE.md

@@ -1,5 +1,11 @@
 # !!!PLEASE READ!!!
 
+## Questions
+
+If you have a question, DO NOT SUBMIT a new issue.
+
+Please ask the question on the Discussions section: https://github.com/nginx-proxy/nginx-proxy/discussions
+
 ## Bugs or Features
 
 If you are logging a bug or feature request, please search the current open issues to see if there is already a bug or feature opened.