[CI] Add reminder about last release step (#3491)

Author: testableapple

.github/workflows/release-publish.yml

@@ -26,3 +26,11 @@ jobs:
           MATCH_PASSWORD: ${{ secrets.MATCH_PASSWORD }}
           APPSTORE_API_KEY: ${{ secrets.APPSTORE_API_KEY }}
         run: bundle exec fastlane publish_release --verbose
+
+      - uses: 8398a7/action-slack@v3
+        with:
+          status: ${{ job.status }}
+          text: "🎉 The new release has been shipped! 🚢\n\n⚠️ <!subteam^S030AAHLDLN>, don't forget to merge `main` back to `develop` from `localhost` using the command: `bundle exec fastlane merge_main`"
+          fields: repo
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}