macadmin-scripts

Update how we check macOS version to deal with older versions of Python compiled against pre-macOS 11 SDK

Several pylint cleanups

Simplify logic when running on pre-macOS 15.6 and when dealing with pre-Big Sur installers

Bring back ability to make installer images for Catalina and older after commit 522fc7f (#133)

Workaround for issue with installer in macOS 15.6