pluggy 1.0.0 release notes

#116 <https://github.com/pytest-dev/pluggy/issues/116>_: Remove deprecated implprefix support. Decorate hook implementations using an instance of HookimplMarker instead. The deprecation was announced in release 0.7.0.
#120 <https://github.com/pytest-dev/pluggy/issues/120>_: Remove the deprecated proc argument to call_historic. Use result_callback instead, which has the same behavior. The deprecation was announced in release 0.7.0.
#265 <https://github.com/pytest-dev/pluggy/issues/265>_: Remove the _Result.result property. Use _Result.get_result() instead. Note that unlike result, get_result() raises the exception if the hook raised. The deprecation was announced in release 0.6.0.
#267 <https://github.com/pytest-dev/pluggy/issues/267>_: Remove official support for Python 3.4.
#272 <https://github.com/pytest-dev/pluggy/issues/272>_: Dropped support for Python 2. Continue to use pluggy 0.13.x for Python 2 support.
#308 <https://github.com/pytest-dev/pluggy/issues/308>_: Remove official support for Python 3.5.
#313 <https://github.com/pytest-dev/pluggy/issues/313>_: The internal pluggy.callers, pluggy.manager and pluggy.hooks are now explicitly marked private by a _ prefix (e.g. pluggy._callers). Only API exported by the top-level pluggy module is considered public.
#59 <https://github.com/pytest-dev/pluggy/issues/59>_: Remove legacy __multicall__ recursive hook calling system. The deprecation was announced in release 0.5.0.

#282 <https://github.com/pytest-dev/pluggy/issues/282>_: When registering a hookimpl which is declared as hookwrapper=True but whose function is not a generator function, a :class:~pluggy.PluginValidationError exception is now raised.

Previously this problem would cause an error only later, when calling the hook.

In the unlikely case that you have a hookwrapper that returns a generator instead of yielding directly, for example:

.. code-block:: python
```
def my_hook_implementation(arg):
    print("before")
    yield
    print("after")


@hookimpl(hookwrapper=True)
def my_hook(arg):
    return my_hook_implementation(arg)
```
change it to use yield from instead:

.. code-block:: python
```
@hookimpl(hookwrapper=True)
def my_hook(arg):
    yield from my_hook_implementation(arg)
```
#309 <https://github.com/pytest-dev/pluggy/issues/309>_: Add official support for Python 3.9.
#251 <https://github.com/pytest-dev/pluggy/issues/251>_: Add specname option to @hookimpl. If specname is provided, it will be used instead of the function name when matching this hook implementation to a hook specification during registration (allowing a plugin to register a hook implementation that was not named the same thing as the corresponding @hookspec).

pluggy 1.0.0