[CLOUDP-350567] Automate PR creation to release helm chart using gh helm repo

[viveksinghggits]

Summary

Per current process when we try to release a version of the helm chart we create a PR to the mongodb/helm-charts repo. Since this is manual task, it's time consuming and error prone.
This PR tries to automate that manual task.

Proof of Work

The successful run here created the PR on helm chart repo successfully.

[2025/10/10 11:56:53.577] INFO     2025-10-10 09:56:53,577 [create_chart_release_pr]  Command succeeded
[2025/10/10 11:56:53.577] INFO     2025-10-10 09:56:53,577 [create_chart_release_pr]  Running command: git push -u origin mck-release-x.y.z in directory /data/mci/7faac8b315a48c50db2b095e7185d1ea/tmp/tmp0nfkyg_w/helm-charts
[2025/10/10 11:56:54.444] INFO     2025-10-10 09:56:54,443 [create_chart_release_pr]  Command succeeded
[2025/10/10 11:56:54.444] INFO     2025-10-10 09:56:54,444 [create_chart_release_pr]  Creating the pull request in the helm-charts repo.
[2025/10/10 11:56:55.762] INFO     2025-10-10 09:56:55,762 [create_chart_release_pr]  Successfully created Pull Request https://github.com/mongodb/helm-charts/pull/516
[2025/10/10 11:56:55.801] Finished command 'subprocess.exec' in function 'create_chart_release_pr' (step 3.2 of 3) in 2.73136881s.

Checklist

• Have you linked a jira ticket and/or is the ticket in the title?
• Have you checked whether your jira ticket required DOCSP changes?
• Have you added changelog file?
  • use skip-changelog label if not needed
  • refer to Changelog files and Release Notes section in CONTRIBUTING.md for more details

[github-actions]

⚠️ (this preview might not be accurate if the PR is not rebased on current master branch)

MCK 1.5.1 Release Notes

[MaciejKaras]

q: what happens if the previous mck-release-{chart_version} branch was merged and we want to make a fix to the same helm chart version? Will this work?

[viveksinghggits]

So, fixing a faulty helm release is an entirely manual process right now that's documented here.

[MaciejKaras]

Code generally looks good, but I have two general comments:

• instead of logging error and returning the error code, it's easier to just repackage the error and raise it again:

except GithubException as e:
    raise Exception(f"ERROR: Could not create Pull Request. GitHub API returned an error: {e.status}, details: {e.data}, original error: {e}")

• the main method does a little too much. It should only handle flags parsing and validation. After that call nested method with validated args that does the hard work.