Mac setup guide does not work - conflicting requirements

[lyricnz]

The docs at https://developers.home-assistant.io/docs/development_environment/#setup-local-repository quite simply do not work. There is a conflict in dependencies on Mac:

pkg_resources.ContextualVersionConflict: (pyobjc-core 8.5.1 (/Users/simonroberts/src/github/home-assistant/core/venv/lib/python3.9/site-packages), Requirement.parse('pyobjc-core>=9.0.1'), {'pyobjc-framework-Cocoa'})

The core devs have said they won't fix this - home-assistant/core#82723 - so please update documentation to stop sending people on a path that doesn't work.

See https://community.home-assistant.io/t/conflicting-requirements-for-pyobjc-core-are-breaking-developer-setup/494129