Provide Apple M1 binaries for pypy

[FirefoxMetzger]

While doing some changes in ImageIO I've noticed that our test suite started to fail because it lacks pre-compiled pyav binaries for MacOS on pypy. I suspect that this is because macos-latest runners now use M1 (xref) which also breaks our test suite for FreeImage tests in a different place.

Would it be possible to add builds for this chipset to the build matrix?

[WyattBlue]

Pypy requires the host to be Apple Silicon in order to build Apple Silicon wheels.

from here

Note: pp39-macosx_arm64, pp310-macosx_arm64 were selected, but can't be built on x86_64 so will be skipped automatically.

[WyattBlue]

Done. #1395