setuptools 61.0.0 breaks macOS installer

[mrclary]

The latest release of setuptools 61.0.0 breaks the macOS installer.
Must constrain to <61.0.0.

I don't know what the underlying issue is, and it may require an update to py2app.

The observed symptoms are:

• The application bundle is named "spyder.app" rather than "Spyder.app"
• The application startup script is named "spyder.app/Contents/MacOS/spyder" rather than "Spyder.app/Contents/MacOS/Spyder"
• The spyder source code is included in both "Spyder.app/Contents/Resources/lib/python39.zip" and "Spyder.app/Contents/Resources/lib/python3.9"

[ccordoba12]

Sorry for closing this one. I thought it was fixed by PR #17547, but now I understand that you opened it so we don't forget to solve it in the future. The only thing is that it can't be tagged for 5.3.0 because our aim is to release that version next Wednesday and I don't think the solution could be found so soon.