I've added utils to the list.

I've done utils since I know there wasn't any pending work associated with it and I already had the resources package to lean on as an example.

I think this is ready for review.  PRs are:

• https://github.com/lsst/utils/pull/110 (mostly done by Tim Jenness , already reviewed by me)
• https://github.com/lsst/daf_butler/pull/620
• https://github.com/lsst/pipe_base/pull/220
• https://github.com/lsst/obs_base/pull/402
• https://github.com/lsst/ctrl_mpexec/pull/157

I don't think it's worthwhile for anybody to look at all of these in detail, and the last two comments on RFC-809 explain all of the non-mechanical, non-configuration changes (as do the commit messages, which are same across packages).  But it'd be good to at least scan those commit messages and spot-check commits other than the big mechanical "run black and isort" ones.

There are also still complaints about MyPy in utils and daf_butler, due to a new version of that appearing on pypi.  If I can get that version with conda before I merge, I'll fix the problems here; if I can't, I'll pin the mypy version in the GHA.  In any case, I think it's best to consider that distinct from the rest of the ticket, even if it ends up on the same branches.

Update: mypy changes were not quite what I expected; the daf_butler GHA had already pinned mypy, and this just needed to be propagated to utils to get that working.  And the problems with mypy in daf_butler were real, and caused by this ticket: black moved around some "type: ignore" annotations.  Both issues now fixed.

I'm happy with these changes.