Log Message:
py-pyobjc: updated to 4.2.2

Version 4.2.2:
Update metadata for Xcode 9.4
The binary release now includes wheels for both variants for the Python.org \ 
installer for python 3.6 and 3.7: 32- and 64-bit for macOS 10.6 or later, and \ 
64-bit only for macOS 10.9 or later.
Ensure the context manager for NSAnimationContext defined in \ 
PyObjCTools.AppCategories actually works.
Fix convenience wrappers for Foundation.NSCache.
Fix convenience wrappers for Foundation.NSHashTable.