Adopt split repo: _python-gke-backup_

[vchudnov-g]

Migrate the split-repo https://github.com/googleapis/python-gke-backup to https://github.com/googleapis/google-cloud-python.

The migration readiness criteria are the following, which we track via GitHub labels on this issue. These criteria apply to the split repo we are migrating from:

• No open issues
• No open PRs
• No handwritten samples
• No system tests
• No client-specific customizations

[parthea]

Wait for cl/546268592 and googleapis/gapic-generator-python#1687

[parthea]

I checked the workarounds in owlbot.py and none of them are needed. We just need to migrate to the standard owlbot.py

[suztomo]

Memo: Issues and pull requests are zero. README or About hasn't been updated. No Cloud document reference.

~/python-gke-backup $ find samples -type f -name "*.py" ! -path "samples/generated_samples/*" | wc -l
       0

Confirmed that https://github.com/googleapis/google-cloud-python/tree/main/packages does not have gke-backup yet.

Next step: "We just need to migrate to the standard owlbot.py". Current owlbot.py: https://github.com/googleapis/python-gke-backup/blob/main/owlbot.py :

for library in s.get_staging_dirs(default_version):
    if clean_up_generated_samples:
        shutil.rmtree("samples/generated_samples", ignore_errors=True)
        clean_up_generated_samples = False

    # Apply workarounds to fix the generated docstrings.
    # Issue filed upstream in https://github.com/googleapis/gapic-generator-python/issues/1345
    s.replace(
        library / f"google/cloud/gke_backup_{library.name}/**/*.py",
        """must:[\n]*
                 - be between 1 and 63 characters long
                \(inclusive\)  - consist of only
                lower-case ASCII letters, numbers, and
                dashes  - start with a lower-case letter
                 - end with a lower-case letter or
                number""",
        """must:

                 - be between 1 and 63 characters long (inclusive) 
                 - consist of only lower-case ASCII letters, numbers, and dashes
                 - start with a lower-case letter
                 - end with a lower-case letter or number"""
    )
...