docs(issue-template): redirect questions to GitHub Discussions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tommysitu

.github/ISSUE_TEMPLATE/question-about-Hoverfly.md

@@ -4,6 +4,8 @@ about: This is not the appropriate channel - please use our Gitter channel
 
 ---
 
-Please use: https://gitter.im/SpectoLabs/hoverfly for questions about `Hoverfly`.
+Please use the link below to raise a question about `Hoverfly`:
+
+https://github.com/SpectoLabs/hoverfly/discussions/new?category=q-a
 
 Only posts that are bug reports or feature/enhancement requests will be addressed here.