Fix typing issue

Author: youtux

src/pytest_bdd/compat.py

@@ -34,7 +34,7 @@ def inject_fixture(request: FixtureRequest, arg: str, value: Any) -> None:
         # if there was already one registered, so we need to force its value
         # to the one we want to inject.
         fixture_def = request._get_active_fixturedef(arg)
-        fixture_def.cached_result = (value, None, None)
+        fixture_def.cached_result = (value, None, None)  # type: ignore
 
 else: