Fix Heroku deployment with Actions

.github/workflows/heroku.yml

@@ -1,22 +1,22 @@
-name: "Deploy"
-
 on:
   push:
     branches:
       - main
       - deploy-with-actions
-
-concurrency: "heroku"
-
+name: Deploy
+concurrency: heroku
 jobs:
   custom-deploy:
     name: "Deploy to Heroku"
     runs-on: ubuntu-latest
     steps:
       - name: Check out repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0 # fetch full clone
+      - name: Install heroku CLI
+        run: |
+          curl https://cli-assets.heroku.com/install-ubuntu.sh | sh
       - name: Heroku login credentials
         run: |
           cat > ~/.netrc <<EOF