Backward sync from Heroku promote to Github deployments

### Required Terms

- [X] I agree to follow this project's [Code of Conduct](https://github.com/heroku/roadmap/blob/main/CODE_OF_CONDUCT.md)
- [X] I have read and accept the [Salesforce Program Agreement](https://www.salesforce.com/company/program-agreement/)

### What service(s) is this request for?

Heroku Flow

### Tell us about what you're trying to solve. What challenges are you facing?

We are using [Heroku Flow](https://www.heroku.com/flow) to continuously deliver our app: When opening a pull request on Github, the Heroku Github integration allows for an automatic creation of a Heroku preview app. This also creates a deployment on Github. Then when the pull request is closed on Github and the changes are pushed to the main branch, the staging pipeline is run. This again creates a (staging) deployment on Github. Now, we use Heroku promote to deploy the app to production pipeline. In this case, there is no Github deployment created.

We are attempting to track the status of issues with Github deployments. Therefore, a sync of the promote in Heroku with Github would be needed. We would expect a (production) deployment on Github, everytime the app is promoted to production on Heroku.