tests: require Python 3.5+ in run-tests.py
We change the version check logic to hard fail if running on
<= 3.5.0. The branch for <3.5 has been deleted. And the >=3.5
branch block has been dedented.
Differential Revision: https://phab.mercurial-scm.org/D12234
[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