Upgrade reusable workflow to use Node 20

Author: textbook

.github/workflows/deploy.yml

@@ -22,7 +22,7 @@ jobs:
       - name: Check out source code
         uses: actions/checkout@v4
       - name: Deploy to Heroku
-        uses: akhileshns/heroku-deploy@v3.12.14
+        uses: akhileshns/heroku-deploy@v3.13.15
         with:
           heroku_api_key: ${{ secrets.HEROKU_API_KEY }}
           heroku_app_name: ${{ vars.HEROKU_APP_NAME }}