pyproject.toml: stop linting in venvs

[allisonkarlitskaya]

Lacking a proper requirements.txt file, we're at the mercy of whatever
got randomly uploaded to pypy last night, and we've been seeing a lot of
breaks lately.

We already run our ruff/mypy/etc. stuff as part of our unit tests
workflow, so let's stop running it in venv. The idea is that we should
pass against the current version of the tasks container (which will
probably shift at some point to being our pinned version of the tasks
container).

While we're at it, drop Python 3.7 (which the world seems to have
collectively decided to stop caring about) and add Python 3.13 (which
has been in Fedora 39 for a while already). Note: we do not drop
Python 3.6 — although it is no longer an officially supported release,
it's used in RHEL 7 and RHEL 8 and Fedora intends to keep packaging it.

[allisonkarlitskaya]

From the unit-tests run:

WARNING: skipping /static-code/test-mypy: no mypy
not ok 9 /static-code/test-ruff
# test/pytest/test_samples.py:18:1: I001 [*] Import block is un-sorted or un-formatted
# Found 1 error.
# [*] 1 fixable with the `--fix` option.
WARNING: skipping /static-code/test-vulture: no vulture
FAIL test/static-code (exit status: 1)

OK, so good — ruff caught one of the problems, but clearly mypy missed the other 😅

Let's get mypy in the tasks container, then.

[allisonkarlitskaya]

Let's get mypy in the tasks container, then.

cockpit-project/cockpituous#595

[allisonkarlitskaya]

FAIL: test/static-code
======================

not ok 7 /static-code/test-mypy
# src/cockpit/peer.py:52: error: Incompatible types in assignment (expression has type "tuple[()]", variable has type "list[Callable[[], None]]")  [assignment]
not ok 9 /static-code/test-ruff
# test/pytest/test_samples.py:18:1: I001 [*] Import block is un-sorted or un-formatted
# Found 1 error.
# [*] 1 fixable with the `--fix` option.
WARNING: skipping /static-code/test-vulture: no vulture
FAIL test/static-code (exit status: 1)

better, but oops: vulture.

[allisonkarlitskaya]

FAIL: test/static-code
======================
not ok 7 /static-code/test-mypy
# src/cockpit/peer.py:52: error: Incompatible types in assignment (expression has type "tuple[()]", variable has type "list[Callable[[], None]]")  [assignment]
not ok 9 /static-code/test-ruff
make[1]: *** [Makefile:8149: check-am] Error 2
make: *** [Makefile:8153: check] Error 2
# test/pytest/test_samples.py:18:1: I001 [*] Import block is un-sorted or un-formatted
# Found 1 error.
# [*] 1 fixable with the `--fix` option.
FAIL test/static-code (exit status: 1)
============================================================================

good!

[martinpitt]

Thanks!