pytest-bdd doesn't support pytest 8.1.0 about pytest-bdd HOT 5 CLOSED

The signature of this (private) function will change in the upcoming
pytest 8.1 release:
https://github.com/pytest-dev/pytest/pull/11785

Additionally, the `iterparentnodeids` function is removed, so
copy/pasting it for now.

I verified that all tests pass when run against pytest main.

fixtures: avoid FixtureDef <-> FixtureManager reference cycle
There is no need to store the FixtureManager on each FixtureDef.

    def __init__(
        self,
        config: Config,
        baseid: Optional[str],
        argname: str,
        func: "_FixtureFunc[FixtureValue]",
        scope: Union[Scope, _ScopeName, Callable[[str, Config], _ScopeName], None],
        params: Optional[Sequence[object]],
        unittest: bool = False,
        ids: Optional[
            Union[Tuple[Optional[object], ...], Callable[[Any], Optional[object]]]
        ] = None,
        *,
        _ispytest: bool = False,
    ) -> None:

def inject_fixture(request: FixtureRequest, arg: str, value: Any) -> None:
    """Inject fixture into pytest fixture request.

    :param request: pytest fixture request
    :param arg: argument name
    :param value: argument value
    """

    fd = FixtureDef(
        fixturemanager=request._fixturemanager,
        baseid=None,
        argname=arg,
        func=lambda: value,
        scope="function",
        params=None,
    )