chore: build wheel with limited api

[lexdene]

Step 1: Standard bdist wheel command

Running the standard bdist_wheel command:

python setup.py bdist_wheel

produces a platform-specific wheel with a filename like:

greenify-0.5.0-cp39-cp39-linux_x86_64.whl

Attempting to install this wheel on a different Python minor version, such as Python 3.10, results in a platform compatibility error:

ERROR: greenify-0.5.0-cp39-cp39-linux_x86_64.whl is not a supported wheel on this platform.

Step 2: Adding limited api Flag

Adding the --py-limited-api parameter to the bdist_wheel command:

python setup.py bdist_wheel --py-limited-api=cp39

produces an ABI3 wheel package with a more compatible filename:

greenify-0.5.0-cp39-abi3-linux_x86_64.whl

However, the name of the compiled shared object (.so) file inside the wheel package is still incorrect:

greenify.cpython-39-x86_64-linux-gnu.so

While the wheel installs successfully on Python 3.10,
running tests raises an ImportError because the module cannot be found under the expected ABI-stable name:

ModuleNotFoundError: No module named 'greenify'

Step 3: Configuring Limited API in setup.py

The correct solution is to explicitly define the Limited API settings within the Extension configuration in setup.py:

setup(
    ext_modules=[
        Extension(
            define_macros=[
                ("Py_LIMITED_API", make_limited_api_macro("3.9")),
            ],
            py_limited_api=True, 
        )
    ]
)

This configuration ensures that both the wheel package name and the internal shared object file name are correct for ABI3 compatibility:

Correct Wheel Name:

greenify-0.5.0-cp39-abi3-linux_x86_64.whl

Correct .so File Name:

greenify.abi3.so

This wheel can now be installed and tested successfully across the specified range of target Python versions, from Python 3.9 to Python 3.14.

[lexdene]

fix #25