Merge tag '2.6.0' into debian/yoga

oslo.versionedobjects 2.6.0 release

meta:version: 2.6.0
meta:diff-start: -
meta:series: yoga
meta:release-type: release
meta:pypi: yes
meta:first: yes
meta:release:Author: Daniel Bengtsson <dbengt@redhat.com>
meta:release:Commit: Daniel Bengtsson <dbengt@redhat.com>
meta:release:Change-Id: Ic32d9fb41107843c3c0f81c96dc86fba24db02eb
meta:release:Code-Review+2: Hervé Beraud <herveberaud.pro@gmail.com>
meta:release:Code-Review+2: Elod Illes <elod.illes@est.tech>
meta:release:Workflow+1: Elod Illes <elod.illes@est.tech>