build: Bump akhileshns/heroku-deploy in the github-actions group

Bumps the github-actions group with 1 update: [akhileshns/heroku-deploy](https://github.com/akhileshns/heroku-deploy).


Updates `akhileshns/heroku-deploy` from 3.14.15 to 4
- [Release notes](https://github.com/akhileshns/heroku-deploy/releases)
- [Commits](AkhileshNS/heroku-deploy@v3.14.15...v4)

---
updated-dependencies:
- dependency-name: akhileshns/heroku-deploy
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/heroku-deploy.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Install Heroku CLI # <- IMPORTANT!!! Make sure the cli is installed before using the action
         run: |
           curl https://cli-assets.heroku.com/install.sh | sh
-      - uses: akhileshns/heroku-deploy@v3.14.15 # This action deploys the content on Heroku
+      - uses: akhileshns/heroku-deploy@v4 # This action deploys the content on Heroku
         with:
           heroku_api_key: ${{secrets.HEROKU_API_KEY}} #The Heroku api key we stored on our repo secret
           heroku_app_name: "djangosnippets" #The name of your heroku app - Must be unique in Heroku