Refactor GitHub Actions workflows, get wheels ready, cross-compile macOS wheels #29

Job	Run time
Wheels (ubuntu-latest / Python 3.8 / Go 1.20.x)	3m 43s
Wheels (macos-latest / Python 3.8 / Go 1.20.x)	4m 28s
Wheels (windows-latest / Python 3.8 / Go 1.20.x)	4m 12s
Wheels (ubuntu-latest / Python 3.8 / Go 1.21.x)	3m 41s
Wheels (macos-latest / Python 3.8 / Go 1.21.x)	4m 29s
Wheels (windows-latest / Python 3.8 / Go 1.21.x)	4m 12s
Wheels (ubuntu-latest / Python 3.12 / Go 1.20.x)	3m 42s
Wheels (macos-latest / Python 3.12 / Go 1.20.x)	4m 29s
Wheels (windows-latest / Python 3.12 / Go 1.20.x)	4m 15s
Wheels (ubuntu-latest / Python 3.12 / Go 1.21.x)	3m 39s
Wheels (macos-latest / Python 3.12 / Go 1.21.x)	4m 26s
Wheels (windows-latest / Python 3.12 / Go 1.21.x)	4m 13s
	49m 29s

Provide feedback