[goal] Migrate cinder-tempest-plugin jobs to focal

As per victoria cycle testing runtime and community goal[1]
we need to migrate upstream CI/CD to Ubuntu Focal(20.04).

Most of the Tempest jobs will be migrate automatically once devstack
base job start running on Focal[2].

Stable jobs testing stable branch needs to keep running on their supported
distro version which is bionic from stein till ussuri.

Keeping barbican jobs running on bionic nodeset till
https://storyboard.openstack.org/#!/story/2007732 is fixed.

[1] https://governance.openstack.org/tc/goals/selected/victoria/migrate-ci-cd-jobs-to-ubuntu-focal.html
[2] https://review.opendev.org/#/c/734700/

Story: #2007865
Task: #40179

Change-Id: Ief046344957004a5ad29337864ace5837d6c553d
diff --git a/.zuul.yaml b/.zuul.yaml
index 0dc96f5..2a04353 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -23,6 +23,12 @@
     description: |
       This is a base job for lvm with lio & tgt targets
     parent: devstack-tempest
+    # TODO(gmann): Remove the below nodeset setting to Bionic once
+    # https://storyboard.openstack.org/#!/story/2007732 is fixed
+    # Once nodeset is removed form here then devstack-tempest job
+    # will automatically run this job on Ubuntu Focal nodeset from
+    # Victoria gate onwards.
+    nodeset: openstack-single-node-bionic
     timeout: 10800
     roles:
       - zuul: opendev.org/openstack/cinderlib
@@ -139,11 +145,13 @@
 - job:
     name: cinder-tempest-plugin-basic-ussuri
     parent: cinder-tempest-plugin-basic
+    nodeset: openstack-single-node-bionic
     override-checkout: stable/ussuri
 
 - job:
     name: cinder-tempest-plugin-basic-train
     parent: cinder-tempest-plugin-basic
+    nodeset: openstack-single-node-bionic
     override-checkout: stable/train
     vars:
       devstack_localrc:
@@ -152,6 +160,7 @@
 - job:
     name: cinder-tempest-plugin-basic-stein
     parent: cinder-tempest-plugin-basic
+    nodeset: openstack-single-node-bionic
     override-checkout: stable/stein
     vars:
       devstack_localrc: