Draft: Resolve "Port release rake task"

What does this MR do and why?

Describe why, not just what. Include links to relevant issues or discussions.

Screenshots, screen recordings, or links to review app

1. DRY_RUN not set. Overwriting file = "n"

2. DRY_RUN not set. Overwriting file = "y", branch is created.

NOTE: This was during the test. I deleted it.

3. DRY_RUN is set. Just logs should appear. No file creation. Not overwriting anything.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Configure a local GitLab Docs environment: https://gitlab.com/gitlab-org/technical-writing-group/gitlab-docs-hugo/-/blob/main/doc/setup.md.
2. DRY_RUN=false make create-stable-branch to run the actual code where it creates the release branch and pushes the release Dockerfile to it. Remove branch after testing from local.
3. DRY_RUN=true make create-stable-branch to run a dry run (not perform any code logic - for practice only).

Merge request acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this merge request.

Closes #39