chore: fix issue template discord link (#21885)

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Fixes #21880

.github/ISSUE_TEMPLATE/config.yml

@@ -4,5 +4,5 @@ contact_links:
     url: https://github.com/denoland/deploy_feedback/
     about: Provide feature requests or bug reports for the Deno Deploy edge runtime.
   - name: 💬 Discord
-    url: https://discord.com/deno
+    url: https://discord.gg/deno
     about: Join our community on Discord.