fix: use supported macOS and Salt versions in CI

[SMillerDev]

This should allow CI to work again

[SMillerDev]

Seems like you can't download just "latest" anymore?

       Traceback (most recent call last):
         File "<stdin>", line 1, in <module>
       ImportError: No module named request
        *  INFO: Running install_macosx_onedir()
       Traceback (most recent call last):
         File "<stdin>", line 1, in <module>
       ImportError: No module named request
        * ERROR: https://repo.saltproject.io/salt/py3/macos/latest/salt--py3-x86_64.pkg failed to download to /tmp/salt--py3-x86_64.pkg
        * ERROR: Failed to run install_macosx_onedir()!!!
       No salt-minion installed, install must have failed!!