Log Message:
py-ruamel-yaml: updated to 0.17.40

0.17.40
- flow style sets are now preserved ( `!!set {a, b, c} )`. Any values specified when
  loading are dropped, including `!!null ""`.
- |
  potential workaround for issue 484: the long_description_content_type \ 
including the variant specification `CommonMark`
  can result in problems on Azure. If you can install from `.tar.gz` using
  `RUAMEL_NO_LONG_DESCRIPTION=1 pip install ruamel.yaml --no-binary :all:` then \ 
the long description, and its
  offending type, are nog included (in the METADATA).
  (Reported by [Coury Ditch](https://sourceforge.net/u/cmditch/profile/))
- links in documentation update (reported by [David \ 
Hoese](https://sourceforge.net/u/daveydave400/profile/))
- Added some `__repr__` for internally used classes