Merge ~cjwatson/launchpad:black-pre-commit-mirror into launchpad:master

[Colin Watson]

pre-commit: Upgrade to black 23.9.1 and use pre-commit mirror

https://black.readthedocs.io/en/stable/change_log.html says "Swapping https://github.com/psf/black to https://github.com/psf/black-pre-commit-mirror in your .pre-commit-config.yaml will make Black about 2x faster". I didn't observe quite that much of an improvement in `pre-commit run -a black`, but it does seem somewhat faster for me, so we might as well.

[Jürgen Gmach (jugmac00)]

If it would not say "official", I'd be a bit worried by the single maintainer, though we certainly can switch back any time.

That all said... it looks like that ruff will also replace black in future, see https://github.com/astral-sh/ruff/issues/1904.

Let's monitor the development, and maybe we can give it a go in a couple of months.

review: Approve

[Colin Watson (cjwatson)]

Yeah, definitely interested in ruff once it matures a bit more.

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 0c51a41..12369b7 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -35,8 +35,8 @@ repos:
             lib/contrib/.*
             |utilities/community-contributions\.py
           )$
--   repo: https://github.com/psf/black
-    rev: 23.3.0
+-   repo: https://github.com/psf/black-pre-commit-mirror
+    rev: 23.9.1
     hooks:
       - id: black
         exclude: |