Wheel support for linux aarch64

Summary Installing cffi on aarch64 via pip using command "pip3 install cffi" tries to build wheel from source code

Problem description cffi don't have wheel for aarch64 on PyPI repository. So, while installing cffi via pip on aarch64, pip builds wheel for same resulting in it takes more time to install cffi. Making wheel available for aarch64 will benefit aarch64 users by minimizing cffi installation time.

Expected Output Pip should be able to download cffi wheel from PyPI repository rather than building it from source code.

@cffi-team, please let me know if I can help you building wheel/uploading to PyPI repository. I am curious to make cffi wheel available for aarch64. It will be a great opportunity for me to work with you.