Make git-client compatible with future guava

[timja]

See jenkinsci/bom#423

and example merged PR in a pipeline component: jenkinsci/workflow-support-plugin#114

cc @MarkEWaite

[timja]

@MarkEWaite could you release this please?

[MarkEWaite]

@MarkEWaite could you release this please?

Sure, though I want some interactive test time before I release it. I will want to release git plugin as well, since it also increases its minimum Jenkins version to 2.249.1, just as the master branch of the git client plugin does.

[timja]

sure you can hold off a bit anyway, I'm going to try a no reflection approach based off of jenkinsci/workflow-support-plugin#117

[timja]

think I'll leave it a lot of classes need vendoring unless @basil wants to give it a go?

[basil]

Vendoring DirectExecutorService seems like more trouble than it's worth. This solution seems fine.

[MarkEWaite]

@timja and @basil I'd like to wait until the official release of JGit 5.11.0 on 17 Mar 2021 before this is released. That also allows me a few days to re-evaluate the user impact of #673. It adds more noise to the console log and provide benefit to a very narrow set of users.

[timja]

makes sense looks like that PR should be tweaked, will follow up later on if required

[MarkEWaite]

Released as git client plugin 3.7.0 17 Mar 2021