* Switch to using sphinx-build
* Fix docs warnings
* Remove test-requirement and fold in requirements, we don't need two
files for this docu only repo.
* Remove unused requirement pytz.
* Update doc requirements
* Remove cruft from setup.cfg and doc/source/conf.py
* Switch to Python3
Change-Id: Iae32f7daa656fca6ae80a750746215fe80d4a0d6
This fix stolen from:
https://review.opendev.org/#/c/658567/
The upper-constraints file wasn't being enforced
when installing dependencies in tox runs which can
lead to failures like installing Sphinx>2.0 in py27
where it's not supported.
This is loosely based on novaclient change
I8be883215f27abb58d15b85e8542cbdf32000bac for the
same kind of issue.
Change-Id: I47d12348e5a80048785a93842f0dfd3060bdbc24