Disabling test matrix with `use_test_matrix=false` leads to error in pre-commit `check-python-versions`

[petschki]

how to reproduce

1. Disable test matrix with

[tox]
use_test_matrix = false

2. run tox -e lint
3. Error:

check-python-versions....................................................Failed
- hook id: check-python-versions
- exit code: 1

setup.py says:          3.9, 3.10, 3.11, 3.12, 3.13
- python_requires says: 3.9, 3.10, 3.11, 3.12, 3.13
tox.ini says:           (empty)

reason

the pre-commit step check-python-versions always checks setup.py,tox.ini but there is no python information left, when I disable test matrix.

notes

this came up during mosaic maintenance for Plone 6.1.x because there we have selenium tests with a manual tests.yml workflow file and I do not want plone/meta test matrix to be launched.