[kolla] Stein release now available

Hi, I'm pleased to announce that the first official Stein cycle releases for Kolla and Kolla Ansible are now available - both 8.0.0. A lot of work has gone into this release, including improving the CI tests, making it the most well tested release yet. Thanks to everyone who contributed. Release notes: https://docs.openstack.org/releasenotes/kolla/stein.html https://docs.openstack.org/releasenotes/kolla-ansible/stein.html Join us on #openstack-kolla to help make the Train cycle release even better. Cheers, Mark