Inheritable pytest configuration

[uwu-420]

Hi, thanks for making pytest!

I'm trying out a monorepo setup which has a pyproject.toml file at the root level and one per sub-project in the monorepo. Ideally, I'd like to set something like

# ./pyproject.toml
[tool.pytest.ini_options]
asyncio_mode = "auto"

only once in the root-level pyproject.toml file and the sub-projects automatically inherits that setting unless overridden in their respective pyproject.toml. Another possibility would be to do it like ruff (see https://docs.astral.sh/ruff/settings/#extend). So something like this in the sub-project's pyproject.toml

# ./sub_project/pyproject.toml
[tool.pytest.ini_options]
extend = "../pyproject.toml"
# Inherits asyncio_mode = "auto"
addopts = "-v"

Cheers!