Webhook event for DMCA notices.

### 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

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

I am wondering if it is possible to add support via webhooks for DMCA notices. We occasionally have some bad apple users on our platform create accounts that violate DMCA policies. While we are always quick to shut them down, we would love if we could automate some of this process. I don't see any existing documentation for automating DMCA notices, but if we could receive a webhook event, we would be able to save some time on our side.

We really hope Heroku can get to this feature as it would be very helpful for us!

No repository files, tests, or entry points are mentioned. Start by reviewing Heroku's existing webhook and DMCA-notice documentation; the work would be complete when DMCA notices can trigger a documented webhook event suitable for automation.

Written by the indexing model from the issue text.