attr: vendor 22.1.0
The previous version was 5 years old, and pytype 2022.06.30 started complaining
about various uses (e.g. seeing `mercurial.thirdparty.attr._make._CountingAttr`
instead of `bytearray`). Hopefully this helps. Additionally, this has official
python 3.11 support.
The `attrs` package is left out, because it is simply a bunch of *.pyi stubs and
`from attr.X import *`, and that's not how they've been used up to this point.
We'd probably need to customize those anyway to
`from mercurial.thirdparty.attr import *`.
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.