1. Clean up some requirements
* Drop the py26 marker for futures; we don't support 2.6 anymore.
* Split hacking version used based on python version.
* Clean up sphinx split -- 2.0+ aren't available to install on py2,
anyway.
Depends-On: https://review.opendev.org/#/c/752340/
Depends-On: https://review.opendev.org/#/c/752736/
(cherry picked from commit 5cb906148709ccc74ca96463fd69a5cae2381edb)
2. Drop lower-constraints testing
The OpenStack community consensus seems to be that it's not worth the
hassle of fixing. *Maybe* we can revisit this if we ever drop py2
support?
Reasonable spot to start on ML threads:
http://lists.openstack.org/pipermail/openstack-discuss/2021-January/019672.html
(cherry picked from commit 06b36ae0e2ee6054162bfb1d9f3cdda39eacbad5)
3. [goal] Migrate testing to ubuntu focal
As per victoria cycle testing runtime and community goal[1]
we need to migrate upstream CI/CD to Ubuntu Focal(20.04).
- Keep py2 functional job run on Bionic node
Story: #2007865
Task: #40221
(cherry picked from commit 9f69908f759daafc99a162b136b24570a2822ee2)
tests: Make test_delete_container_versions less flakey
Hammering that test in a tight loop, I'd often see failures due to
ordering issues. Make the delete single-threaded to avoid that.
(cherry picked from commit c73792c2e55e4fbdff78a192a991e064a317e840)
Change-Id: I5a6ba8e65c23ada7297f6684dcbdd886591d0af5