run-tests: remove obsolete coverage check and packaging import (issue6805)
This removes an obsolete `coverage` version check (version from a decade ago).
This also conveniently removes the dependency over `packaging.version`,
which requires some additional installation since Python 3.10.
[build-system]
requires = ["setuptools", "wheel"]
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true