setuptools is now emitting the following warning when building nova:
UserWarning: Usage of dash-separated 'python-requires' will not be
supported in future versions. Please use the underscore name
Do as it says. While we're here, we update a few other options to use
their new variants and add some additional metadata. This leaves one
Warning: Unknown distribution option: 'requires_python'
That unfortunately cannot be fixed here and requires a separate fix in
Signed-off-by: Stephen Finucane <email@example.com>