user controlled pytest-cache separation by environment

[RonnyPfannschmidt]

pytest/src/_pytest/cacheprovider.py

Lines 480 to 481 in f6aa9d6

	if "TOX_ENV_DIR" in os.environ:
	cache_dir_default = os.path.join(os.environ["TOX_ENV_DIR"], cache_dir_default)

adds a utterly hackish way to have pytest-cache by tox env
we should make it more nuanced and aware of more types of session (nox ,hatch, virtualenvwrapper)