relax click dependency to make it possible to satisfy other project dependencies

[ned2]

Currently click is pinned at version 7.0, which makes satisfying all dependency constraints for a project that also has shub installed difficult, especially given that click 7.0 was released in September 2018, with the latest version being 8.0.1.

Is there a reason for pinning click? If not, could this be relaxed to make it easier to use with other packages in the same virtual environment?

If, on the other the shub package is not intended to be an installed library and rather just an executable, perhaps the documentation need to make this clear, and suggest installing the package with a tool like pipx, which creates a standalone virtual environment, rather than with pip into the current environment.

[muscovitebob]

This is painful especially with the new pip resolver algorithm which will attempt to find a satisfactory dependency anyway.

[apalala]

I'm working on fixing this. It consists mostly on dropping support for Python 2.7, but I found the same has to be done on python-scrapinghub for the fix to be complete.