Setuptools is deprecating dash-separated keys on setup.cfg

[abravalheri]

It seems that the latest versions of setuptools are deprecating dash-separated keys on setup.cfg, and we have a mix of them our template for setup.cfg.

The warnings can be seen by running tox -e build

/tmp/build-env-cjhu26rf/lib/python3.8/site-packages/setuptools/dist.py:634: UserWarning: Usage of dash-separated 'author-email' will not be supported in future versions. Please use the underscore name 'author_email' instead
  warnings.warn(
/tmp/build-env-cjhu26rf/lib/python3.8/site-packages/setuptools/dist.py:634: UserWarning: Usage of dash-separated 'project-urls' will not be supported in future versions. Please use the underscore name 'project_urls' instead
  warnings.warn(
/tmp/build-env-cjhu26rf/lib/python3.8/site-packages/setuptools/dist.py:634: UserWarning: Usage of dash-separated 'long-description' will not be supported in future versions. Please use the underscore name 'long_description' instead
  warnings.warn(
/tmp/build-env-cjhu26rf/lib/python3.8/site-packages/setuptools/dist.py:634: UserWarning: Usage of dash-separated 'long-description-content-type' will not be supported in future versions. Please use the underscore name 'long_description_content_type' instead
  warnings.warn(
/tmp/build-env-cjhu26rf/lib/python3.8/site-packages/setuptools/dist.py:634: UserWarning: Usage of dash-separated 'no-vcs' will not be supported in future versions. Please use the underscore name 'no_vcs' instead
  warnings.warn(
/tmp/build-env-cjhu26rf/lib/python3.8/site-packages/setuptools/dist.py:634: UserWarning: Usage of dash-separated 'max-line-length' will not be supported in future versions. Please use the underscore name 'max_line_length' instead
  warnings.warn(
/tmp/build-env-cjhu26rf/lib/python3.8/site-packages/setuptools/dist.py:634: UserWarning: Usage of dash-separated 'extend-ignore' will not be supported in future versions. Please use the underscore name 'extend_ignore' instead
  warnings.warn(

[abravalheri]

@FlorianWilhelm do you think we should do automatic conversions inside update.py, or just change the templates? (the first option is more cumbersome to implement, but it would fix problems transparently to the users; the second option is very lightweight and could even be considered in a bug-fix release)

[abravalheri]

For the time being ,we can follow the simple solution and guarantee new projects will not have dashed keys (PR #419). The users of existing projects can still run putup . --update --force (and do the appropriate merging, e.g. using git mergetool).

@FlorianWilhelm (and any other user that might read this issue in the future) please feel free to reopen the issue.