[misc] Post release to forum (#4312)

.github/workflows/forum.yml

@@ -0,0 +1,18 @@
+name: Post release topic on Discourse
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  post:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: roots/discourse-topic-github-release-action@main
+        with:
+          discourse-api-key: ${{ secrets.DISCOURSE_RELEASES_API_KEY }}
+          discourse-base-url: https://forum.netbird.io
+          discourse-author-username: NetBird
+          discourse-category: 17
+          discourse-tags:
+            releases