Log Message:
py-test: updated to 4.6.6

pytest 4.6.6:
Bug Fixes
* Fixed using multiple short options together in the command-line (for example \ 
-vs) in Python 3.8+.
* Replace importlib_metadata backport with importlib.metadata from the standard \ 
library on Python 3.8+.
* Fix “lexer” being used when uploading to bpaste.net from --pastebin to \ 
“text”.
* Fix warnings about deprecated cmp attribute in attrs>=19.2.

Trivial/Internal Changes
* Fixes python version checks (detected by flake8-2020) in case python4 becomes \ 
a thing.