Feature request: upgrade action versions and regenerate actions.lock #140

Summary

Would it be possible to add a local upgrade operation that updates action version tags in YAML and regenerates actions.lock in one invocation?

Current behavior

--relock refreshes locked SHAs for existing mutable refs. It does not select newer version tags or update uses: references.

Upgrading to a newer version therefore requires updating the YAML references separately before regenerating the lockfile.

Expected behavior

An upgrade operation would:

• Update action version references in workflows and local composite actions.
• Keep readable version tags in YAML, with resolved commit SHAs in actions.lock.
• Regenerate the affected lock entries, including the required transitive dependencies.

For example, upgrading actions/checkout@v7.0.0 to actions/checkout@v7.0.1 would update both the YAML reference and the corresponding lock entries.

Related context

PR #30 removed the previous update command during the transition to a detached lockfile and mentioned adding it separately.

Would a local upgrade operation still fit the intended scope of the project?