Test git 5.1.0 and git client 4.4.0 incremental builds

[MarkEWaite]

Test git 5.1.0 and git client 4.4.0 incremental builds

Includes updates for

• JGit 6.5.0 to 6.6.0
  release notes
  git client plugin pull request

• Require Jenkins 2.387.3 or newer
  git client plugin pull request
  git plugin pull request

• HTMLUnit 2.x to 3.x
  Jenkins test harness pull request
  git client plugin pull request
  git plugin pull request

Testing done

Interactive testing of both updates with 2.401.1 completed successfully. Verified working with Linux controller running Java 11 and a wide range of agent operating systems and versions.

mvn -P 2.375.x --pl sample-plugin verify passes

mvn --pl sample-plugin verify passes

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 demonstrates feature works or fixes the issue

[MarkEWaite]

Based on the 400+ test results reported, I'm proceeding with the release of git client plugin 4.4.0 and git plugin 5.1.0. They won't be usable in the plugin bill of materials until the following plugins are released with an update to use the test jar provided by git plugin 5.1.0:

• branch-api - Require Jenkins 2.387.3 or newer branch-api-plugin#379
• workflow-cps - Require Jenkins 2.387.3 or newer workflow-cps-plugin#723
• workflow-multibranch - Require Jenkins 2.387.3 or newer workflow-multibranch-plugin#258
• workflow-scm-step - Require Jenkins 2.387.3 or newer workflow-scm-step-plugin#126
• pipeline-model-definition - Require Jenkins 2.387.3 or newer pipeline-model-definition-plugin#623
• pipeline-build-step - Require Jenkins 2.387.3 or newer pipeline-build-step-plugin#120