Proposal: Remove PackageMaker package generator
Apple deprecated PackageMaker in 2013 with Xcode 4.6 (see release notes), and we formally deprecated the PackageMaker package generator in CMake 3.17 (see !4309 (merged)). The CPack implementation shares code between the PackageMaker and productbuild generators, but we are gaining new features that are specific to productbuild in CMake 3.23. It will become increasingly harder to keep PackageMaker working and free from errors, since most testing machines probably won't even have PackageMaker installed any more.
I propose we remove the PackageMaker generator completely in CMake 3.24. If we agree, then it might be worthwhile highlighting in the CMake 3.23 release notes that it will be the last version that provides the PackageMaker generator.