Log Message:
py-decorator: updated to 4.4.0

4.4.0:
Fixed a regression with decorator factories breaking the case with no
arguments by going back to the syntax used in version 4.2.
Accepted a small fix from Eric Larson (https://github.com/larsoner) affecting
isgeneratorfunction for old Python versions.
Moved the documentation from ReadTheDocs to GitHub to simplify the
release process and replaced ReStructuredText with Markdown: it is
an inferior solution, but it works better with GitHub and it is good enough.