build(deps): bump akhileshns/heroku-deploy from 3.14.15 to 3.15.15 (#3143)

Bumps [akhileshns/heroku-deploy](https://github.com/akhileshns/heroku-deploy) from 3.14.15 to 3.15.15.
- [Release notes](https://github.com/akhileshns/heroku-deploy/releases)
- [Commits](AkhileshNS/heroku-deploy@v3.14.15...v3.15.15)

---
updated-dependencies:
- dependency-name: akhileshns/heroku-deploy
  dependency-version: 3.15.15
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]

.github/workflows/deploy.yml

@@ -40,7 +40,7 @@ jobs:
           git push origin v${{steps.check.outputs.version}}
       - name: Deploy to Heroku
         if: steps.check.outputs.changed == 'true'
-        uses: akhileshns/heroku-deploy@v3.14.15
+        uses: akhileshns/heroku-deploy@v3.15.15
         with:
           heroku_api_key: ${{secrets.HEROKU_API_KEY}}
           heroku_app_name: "mdn-bcd-collector"