[Feature Request] Support auto-deletion for branches if the backport PR is closed about backport-action HOT 1 CLOSED

Hiya @FogDong 👋 Thanks for raising this.

I've had a look at your proposal, but there are some difficulties with this:

• none of the GitHub APIs (REST/GraphQL/CLI) allow setting the auto-deletion of the pull request branch before merging it
• the backport-action is only concerned with creating a pull request; maintainers should review the new pull request and decide whether to merge it or not

So, I don't see a possibility for supporting this unless we expand the scope of the backport-action to auto-merge the created pull request. We should discuss that in a separate issue if that's a feature you'd like to see.

As a workaround, you could:

• enable auto-deletion of branches after merging a pull request in your repo
• set up a workflow to automatically delete the branch of backport pull requests using one of the existing delete branch actions

from backport-action.