Fixed/relaxed version specifications for click, jsonref, and jsonschema.

[mheilman]

Fixes #376

[mheilman]

To test this, I uninstalled click, ran pip install -e . to reinstall civis-python, and the latest version of click (7.1.1) was installed.

[jacksonllee]

Should we add pip list as the last step in the build, around and after here? That way, the build can tell us what's in a clean-slate environment for this sort of issues/bugs.

[stephen-hoover]

LGTM, and thank you for including jsonref and jsonschema as well.

[mheilman]

@jacksonllee, travis already shows the versions of packages that get installed, if you expand the logs a bit (e.g., Successfully installed cbor2-5.0.1 civis click-7.1.1 cloudpickle-1.3.0 importlib-metadata-1.5.0 jsonref-0.2 jsonschema-3.2.0 pubnub-4.5.0 pycryptodomex-3.9.7 pyrsistent-0.15.7 zipp-3.1.0 here). Does that satisfy your request for a pip list?

[jacksonllee]

travis already shows the versions of packages that get installed, if you expand the logs a bit

Yeah I'm aware of that, though IMO it's not as nice as pip list or pip freeze as a final report. :-) Feel free to ignore my comment and merge this in.