Always build universal binaries on macOS

[paulfd]

No description provided.

[redtide]

I think this is not necessary here, I thought we could make st_audiofile a standalone repo with its own CI workflow and do this there instead.

[paulfd]

Doing both is also an option!

[redtide]

I still have the same idea about not to "abuse" of CI resources (after the Travis experience...). Other than that, builds are quite a lot and takes forever if there is some activity on the repo.
So if you care to set the universal build here, then forget my previous comment.

[redtide]

Anyway.. this is strange, disabling WAVPACK_ENABLE_ASM was working before, unless it's something different this time. Is it possible that it needs to cache the var in CMake?

[redtide]

Erm... my bad, I forgot about this, and also confused for some reason that the issue was on the plugins side.