
1. Sync sphinx dependency with global requirements. It caps python 2 since sphinx 2.0 no longer supports Python 2.7. 2. Update some URLs to latest 3. Update the UPPER_CONSTRAINTS_FILE for tox[1] [1]: http://lists.openstack.org/pipermail/openstack-discuss/2019-May/006478.html Change-Id: Ief1980f0ff6c13ff0370b22267f2ef9baaa1ab64