GitHub Actions doesn't send slack notifications for Release failures in Heroku App

In my workflow yaml file, I have a step that sends slack notifications if the deployment step fails i.e if it exits with a non-zero exit status. The build succeeds in Heroku but the release phase fails and the app fails to deploy to the server. We don't get notified of this release failure. How can I modify the code such that it sends us release failure notifications as well? Thank you.

- name: send failure notification to slack
  if: steps.deployment.outputs.exitcode != '0'
  uses: slackapi/slack-github-action@v1.19
  with: 
    channel-id: 'insert-channel-id'
    slack-message: 'insert-slack-message'
  env:
    SLACK_BOT_TOKEN: $