Add stubs for pluggy==1.2.0

[hoefling]

This PR suggests to add stubs for the pluggy package of the current version 1.2.0. The reason for this is that although pluggy itself is (almost) completely typed, the package ships no PEP 561 marker yet, as there is no consensus about what types to expose, see pytest-dev/pluggy#414.

[AlexWaygood]

Thanks! Looks pretty good; a few remarks below.

Seems a bit unfortunate to add these stubs given how heavily typed the runtime package is, but if they don't want to add a py.typed file, I guess I'm okay with adding these.

[hoefling]

@AlexWaygood

Seems a bit unfortunate to add these stubs given how heavily typed the runtime package is, but if they don't want to add a py.typed file, I guess I'm okay with adding these.

TBH I was expecting the package to expose type hints in 1.2.0, but since it is postponed, I'd rather have a types-pluggy for a year or so out there to not to carry around my own stubs along in every pytest plugin repo. Once the type hints are exposed, I think I'll be the first one to drop the stubs again and carry one less types-* dependency around.

Another (not so obvious and rather a personal) benefit from this PR is that thanks to you, I'm getting a great sync on the latest typeshed development progress ;-)

[AlexWaygood]

Nearly there, I think!

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

pytest (https://github.com/pytest-dev/pytest)
+ src/_pytest/config/__init__.py:471: error: Incompatible types in assignment (expression has type "dict[str, bool]", variable has type "_HookSpecOpts | None")  [assignment]
+ src/_pytest/config/__init__.py:734: error: "PytestPluginManager" has no attribute "_name2plugin"  [attr-defined]
+ src/_pytest/config/__init__.py:735: error: "PytestPluginManager" has no attribute "_name2plugin"  [attr-defined]
+ src/_pytest/config/__init__.py:737: error: "PytestPluginManager" has no attribute "_name2plugin"  [attr-defined]
+ src/_pytest/config/__init__.py:738: error: "PytestPluginManager" has no attribute "_name2plugin"  [attr-defined]
+ src/_pytest/config/__init__.py:1069: error: Incompatible types in assignment (expression has type "Any | None", variable has type "TerminalReporter")  [assignment]
+ src/_pytest/pytester.py:754: error: "PytestPluginManager" has no attribute "reprec"  [attr-defined]
+ src/_pytest/logging.py:666: error: Argument 1 to "_LiveLoggingStreamHandler" has incompatible type "Any | None"; expected "TerminalReporter"  [arg-type]
+ src/_pytest/helpconfig.py:165: error: Item "None" of "Any | None" has no attribute "_tw"  [union-attr]
+ src/_pytest/helpconfig.py:230: error: Item "None" of "Any | None" has no attribute "stats"  [union-attr]
+ testing/test_pluginmanager.py:245: error: Item "None" of "Any | None" has no attribute "__name__"  [union-attr]
+ testing/test_pluginmanager.py:246: error: Item "None" of "Any | None" has no attribute "__name__"  [union-attr]
+ testing/test_pluginmanager.py:339: error: Item "None" of "Any | None" has no attribute "__name__"  [union-attr]
+ testing/test_pluginmanager.py:354: error: Item "None" of "Any | None" has no attribute "x"  [union-attr]

[AlexWaygood]

LGTM. Thanks!