ci: broadcast release on discord (#1594)

Author: innocenzi

.github/workflows/create-gh-release.yml

@@ -36,3 +36,22 @@ jobs:
         with:
           body_path: release_notes.txt
           tag_name: ${{ github.ref_name }}
+
+      - name: Broadcast release on Discord
+        env:
+          DISCORD_WEBHOOK: ${{ secrets.DISCORD_RELEASE_WEBHOOK_URL }}
+          RELEASE_BODY: ${{ steps.generate_release_notes.outputs.changelog }}
+          RELEASE_URL: https://github.com/${{ github.repository }}/releases/tag/${{ github.ref_name }}
+          RELEASE_TAG: ${{ github.ref_name }}
+        run: |
+          processed_body=$(echo "$RELEASE_BODY" | perl -0777 -pe 's/\n*### (\S+) (.+?)\n+/\n### `\1`  \2\n/g')
+          final_content=$(printf "%s\n%s" "-# Read the [GitHub release](<${RELEASE_URL}>)." "$processed_body")
+          jq -n \
+            --arg content "$final_content" \
+            --arg username "Tempest ${RELEASE_TAG}" \
+            '{
+              content: $content,
+              username: $username
+            }' | curl -X POST "$DISCORD_WEBHOOK" \
+            -H "Content-Type: application/json" \
+            -d @-