GH-36243: [Dev] Remove PR workflow label as part of merge

[raulcd]

Rationale for this change

Those labels are unnecessary once they are merged. There was a conversation on Zulip about removing them in the past.

What changes are included in this PR?

Once we merge a PR we remove labels that starts with the PR workflow prefix awaiting.

Are these changes tested?

I have tested the code against an old testing PR I have here: #35323
The label was removed successfully.

Are there any user-facing changes?

No

• Closes: [Dev] Remove PR workflow labels once PR is merged #36243

[github-actions]

⚠️ GitHub issue #36243 has been automatically assigned in GitHub to PR creator.

[raulcd]

@pitrou I think you asked for this in the past. I can do a cleanup of labels once this is merged so we remove them from closed PRs.

[raulcd]

btw based on the API if the result is 200 the merge was successful and merged will always be true.
https://docs.github.com/en/rest/pulls/pulls?apiVersion=2022-11-28#merge-a-pull-request
I am sure we can mark this as False if those are not successful.

[kou]

+1

[conbench-apache-arrow]

Conbench analyzed the 6 benchmark runs on commit 5c2c7acb.

There were 8 benchmark results indicating a performance regression:

• Commit Run on ursa-thinkcentre-m75q at 2023-06-27 02:18:21Z

  • params=<STATIC_VECTOR(std::shared_ptr)>, source=cpp-micro, suite=arrow-small-vector-benchmark

• Commit Run on arm64-t4g-linux-compute at 2023-06-25 07:22:59Z

  • params=simple_expression/batch_size:10000/real_time, source=cpp-micro, suite=arrow-acero-project-benchmark

• and 6 more (see the report linked below)

The full Conbench report has more details.