`--keep` does not show available updates

Rationale

My .pre-commit-config.yaml looks like

...
- repo: https://gitlab.com/vojko.pribudic.foss/pre-commit-update
  rev: v0.6.1
  hooks:
  - id: pre-commit-update
    args: [--dry-run]
...

which yields

$ pre-commit run pre-commit-update --all-files
pre-commit-update........................................................Failed
- hook id: pre-commit-update
- exit code: 1

✘ bandit - 1.8.2 -> 1.8.3   
✘ pyright-python - v1.1.393 -> v1.1.395   
✘ ruff-pre-commit - v0.9.4 -> v0.9.8   
Changes detected

When changing to:

...
- repo: https://gitlab.com/vojko.pribudic.foss/pre-commit-update
  rev: v0.6.1
  hooks:
  - id: pre-commit-update
    args: [--dry-run, --keep, pyright-python]
...

I get

$ pre-commit run pre-commit-update --all-files
pre-commit-update........................................................Failed
- hook id: pre-commit-update
- exit code: 1

✘ bandit - 1.8.2 -> 1.8.3   
✘ ruff-pre-commit - v0.9.4 -> v0.9.8   
Changes detected

According to the description of the option --keep It should still show the new version, right?

Type (select one)

• Bug
• Feature request
• Suggestion

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• No similar issue/feature request/suggestion exists