Add py as dependency to remeditate AttributeError: module 'py' has no attribute 'io'

[ahebrank]

See #816 .

pytest has removed py as a dependency as of 7.2.0 (pytest-dev/pytest#10396), but tavern still requires it. Test failures produce an internal error AttributeError: module 'py' has no attribute 'io' without this dependency.

[michaelboulton]

I think there is some issue with the way tox caching is working in the github action. I don't know why it keeps failing (due to it not actually installing py) when it's explicitly listed as a dependency

[i540608]

@michaelboulton Hi,
is it possible to remove the Py from the release dependencies and use different file for test dependencies, because the Py has quite high-level security vulnerability and it will trigger security scanners for my projects;

As the Py is itself deprecated, then it's highly likely that maintainers of the Py will not push the fix

[michaelboulton]

It may be deprecated but pytest have also vendored part of the library pytest-dev/pytest#10396 , not the 'io' part which is also used by tavern. It means reaching into more internal pytest code.