Add Discord webhook for published releases (#1684)

.github/workflows/discord_webhook.yml

@@ -0,0 +1,22 @@
+on:
+  release:
+    types: [published]
+    
+jobs:
+  message:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Discord Webhook Action
+      uses: tsickert/discord-webhook@v5.3.0
+      with:
+        webhook-url: ${{ secrets.DISCORD_WEBHOOK_URL }}
+        content: |
+          📣 Zed ${{ github.event.release.name }} was just released!
+          
+          Restart your Zed or head to https://zed.dev/releases to grab it.
+        
+          ```md
+          ### Changelog
+          
+          ${{ github.event.release.body }}
+          ```