Delete branch after close PR in merged stack

[levibostian]

Creating issue from discussion

Expected behavior

• Create a new branch off main.
• Create commits on new branch.
• Run git spr update to create stack.
• Run git spr merge when ready to merge stack.
• All open PRs get merged/closed by spr. Commits get merged into main. And all spr/ branches on my remote repository that were created by spr to create the PR stack all get deleted.

Actual behavior

• ...
• My github repo after running git spr merge will still have spr/ branches that did not get deleted. I need to manually go into github and delete those branches. I have noticed that the branches that do not get deleted are branches that are associated with the PRs that got closed (not the one that got merged by spr).

[levibostian]

Opened a PR with an attempt at implementing this feature.

I got stuck on writing tests. Otherwise, I think the feature is as simple as what the PR added?

Any feedback is welcome. Thanks for the consideration of this feature!