Run `pre-commit autoupdate`
Run `pre-commit autoupdate`

black was broken per psf/black#2964, so our pre-commit config needed
updating to reference the newer version. This provided a prompt to
update all pre-commit hook versions.

DemocracyClub/UK-Polling-Stations,DemocracyClub/UK-Polling-Stations,DemocracyClub/UK-Polling-Stations