support pytest 9

[sverhoeven]

Pytest v9 has been released with native pyproject.toml support

python-template/template/pyproject.toml.jinja

Lines 95 to 96 in 07e120e

	[tool.pytest.ini_options]
	testpaths = ["tests"]

Can now be written as

[tool.pytest]
testpaths = ["tests"] 

As pytest v9 is a major version bump and new, we should take care that pytest-* packages like pytest-cov are compatible.

[sverhoeven]

Possibly also change import mode from prepend to importlib, see https://docs.pytest.org/en/stable/explanation/goodpractices.html#choosing-an-import-mode.

This allows to have test files with same file name like

tests/a/test_view.py
tests/b/test_view.py

Pytest advises this for new projects.