Split up `dev` dependency group

[korikuzma]

Currently the dev optional dependency group is:

vrs-python/pyproject.toml

Lines 56 to 69 in 4303546

	dev = [
	# tests
	"pytest",
	"pytest-cov",
	"pytest-vcr",
	"vcrpy>=7.0.0",
	"pyyaml",
	# style
	"pre-commit>=4.0.1",
	"ruff==0.9.4",
	# docs
	"sphinx",
	"sphinx_rtd_theme",
	]

We should consider breaking this out into tests, dev and docs:

dev = [
    "pre-commit>=4.0.1",
    "ruff==0.9.4",
]
tests = [
    "pytest",
    "pytest-cov",
    "pytest-vcr",
    "vcrpy>=7.0.0",
    "pyyaml",
]
docs = [
    "sphinx",
    "sphinx_rtd_theme",
]