Setuptools v54.1.0 introduces a warning that the use of
dash-separated options in 'setup.cfg' will not be supported
in a future version [1].
Get ahead of the issue by replacing the dashes with underscores.
Without this, we see 'UserWarning' messages
like the following on new enough
versions of setuptools:
UserWarning: Usage of dash-separated 'description-file' will not be
supported in future versions. Please use the underscore name
'description_file' instead
[1] https://github.com/pypa/setuptools/commit/a2e9ae4cb
Change-Id: I5ddb624d6f466a8651c3e8c3e4d1dad2dca6a298