CI: update macOS to v12, removed deprecated macOS-10.15
CI: update macOS to v12, removed deprecated macOS-10.15

libmapper/libmapper,malloch/libmapper,malloch/libmapper,libmapper/libmapper,libmapper/libmapper,malloch/libmapper,malloch/libmapper,libmapper/libmapper,malloch/libmapper,libmapper/libmapper,libmapper/libmapper,malloch/libmapper