openstacksdk 0.31.0 release

meta:version: 0.31.0
meta:diff-start: -
meta:series: train
meta:release-type: release
meta:pypi: yes
meta:first: no
meta:release:Author: Eric Fried <openstack@fried.cc>
meta:release:Commit: Eric Fried <openstack@fried.cc>
meta:release:Change-Id: I0c5bb1a0b193b15e8551544c82b37e83b4ab474c
meta:release:Code-Review+1: Monty Taylor <mordred@inaugust.com>
meta:release:Code-Review+2: Thierry Carrez <thierry@openstack.org>
meta:release:Code-Review+2: Sean McGinnis <sean.mcginnis@gmail.com>
meta:release:Workflow+1: Sean McGinnis <sean.mcginnis@gmail.com>