Publish new version (2.2.0?) with worktree support

[SethTisue]

motivation: to ship #248 (merged) and #243 (awaiting review feedback) , plus let's get the cleanups in #249 in

then we'll want to pull it in downstream in sbt-ci-release, which is how many of the projects I work on get their sbt-git

[BillyAutrey]

We'll likely want to cross-publish to sbt 2.0 with this as well. #257

[SethTisue]

Eugene was faster: https://github.com/sbt/sbt-git/releases/tag/v2.1.0

but #243 is still pending, so I've narrowed the title/scope of this ticket

[SethTisue]

Hmm, I'm not sure why I thought it made sense to leave this ticket open. #243 remains pending; presumably if and when it is merged, a release will follow.