…#3281)

- Replaces `python setup.py install` with `pip install` in the Docker image
- Removes the hard-coded `repoze.lru` (`-` to `.`) workaround in `pin-helper`

The issue arose because `pip-compile` switches `.` to `-` when following [PEP-0503](https://peps.python.org/pep-0503/#normalized-names) package name normalization rules. While `pip` seamlessly handles the aliased name (installing the package with `.`), `setuptools` does not manage the mismatch well. By moving to `pip install`, we avoid the naming conflict entirely and prevent future mishaps.

* Add a `pr-complete` task that we can require before merging PRs

The task does nothing, always succeeds but depends on all test tasks passing.

* Add ui tasks to `pr-complete` dependencies

* chore: Update tox to version 4

* chore: Update dockerfile to remove some tox warnings

* chore: update python dependencies

* Fix formatting for what black now expects

The new token I just added is a format that isn't supported in .dockercfg