Test git client replacement of whatchanged

[MarkEWaite]

Test git client replacement of whatchanged

https://issues.jenkins.io/browse/JENKINS-76004

Source pull request:

• [JENKINS-76004] Use git log instead of git whatchanged for changelog git-client-plugin#1326

Verification pull request in the git plugin:

• Require Jenkins 2.504.3 or newer git-plugin#1796

Testing done

Automated tests pass. Rely on ci.jenkins.io for deeper testing.

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests that demonstrate the feature works or the issue is fixed

[MarkEWaite]

Closing because the tests confirm that the git client plugin changes are working as expected.

Also confirms that the analysis from @basil is correct related to the warnings plugin and its related plugins. Will need a new release of one or more of those plugins or needs a revert of the recent plugin-util-api upgrade.

Details at #5544 (comment)