⬆️ Bump akhileshns/heroku-deploy from v3.6.8 to v3.7.8

Bumps [akhileshns/heroku-deploy](https://github.com/akhileshns/heroku-deploy) from v3.6.8 to v3.7.8.
- [Release notes](https://github.com/akhileshns/heroku-deploy/releases)
- [Commits](AkhileshNS/heroku-deploy@v3.6.8...7a09db9)

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/deploy.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v2.3.4
-      - uses: akhileshns/heroku-deploy@v3.6.8
+      - uses: akhileshns/heroku-deploy@v3.7.8
         with:
           heroku_api_key: ${{ secrets.HEROKU_API_KEY }}
           heroku_app_name: staart-api