cpack: allow customization of .dmg filesystem when invoking hdiutil
When CPack invokes hdiutil to create an archive here:
the filesystem type is hard-coded as HFS+. Unfortunately, right now there's a bug on M1 Big Sur that prevents creation of a .dmg of this format:
Could CPack allow users to customize the format used here; e.g. via something like
In addition, now that APFS is the standard filesystem for most macOS machines, it might be worth considering whether the default could (eventually) be changed as well.