Linter complains when running tox

[rholmboe]

Running tox linters after #61 is merged will exit zero, but there is issues in both subgit/ and tests/ folders, so creating an issue.

After issued are fixed, remove tox.ini:31 ... --exit-zero and re-run tox -e linters to verify.

$ tox -e linters
ROOT: tox-gh-actions won't override envlist because tox is not running in GitHub Actions
linters: commands[0]> ruff --exit-zero subgit/ tests/
subgit/core.py:896:32: C413 Unnecessary `list` call around `sorted()`
subgit/core.py:903:32: C413 Unnecessary `list` call around `sorted()`
subgit/core.py:909:32: C413 Unnecessary `list` call around `sorted()`
tests/conftest.py:6:1: I001 [*] Import block is un-sorted or un-formatted
tests/conftest.py:17:47: B026 Star-arg unpacking after a keyword argument is strongly discouraged
tests/test_core.py:4:1: I001 [*] Import block is un-sorted or un-formatted
tests/test_core_query.py:4:1: I001 [*] Import block is un-sorted or un-formatted
tests/test_core_query.py:22:9: B015 Pointless comparison. This comparison does nothing but waste CPU instructions. Either prepend `assert` or remove it.
Found 8 errors.
[*] 3 potentially fixable with the --fix option.
  linters: OK (0.04=setup[0.03]+cmd[0.01] seconds)
  congratulations :) (0.08 seconds)