Currently on py3.9, py3.10 the MACOS_DEPLOYMENT_TARGET is 10.13, which can work but will fail when using the system libffi on variadac code due to #3879. This is CPython python/cpython#58732. The download page does state we support 10.15 and up. I think we should drop the older macos versions, it will hopefully prevent end user issues.

Also: the arm64 builds should have sysconfig's MACOS_DEPLOYMENT_TARGET == 11.0