[CI] Move to CentOS Stream

CentOS Stream 8 (aka CentOS 8 Stream) is the currently
supported runtime platform. [0]

DevStack works with CentOS Stream only now. [1]
This patch prepares the ground to drop the devstack-*-centos-8
nodeset.

[0] https://governance.openstack.org/tc/reference/runtimes/xena.html
[1] https://review.opendev.org/c/openstack/devstack/+/759122

Change-Id: I53231cb6b00a57927b3d19115f64117f7cd755ed
diff --git a/.zuul.yaml b/.zuul.yaml
index be5f933..4b61254 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -5,7 +5,7 @@
     check:
       jobs:
         - cinder-tempest-plugin-lvm-lio-barbican
-        - cinder-tempest-plugin-lvm-lio-barbican-centos-8:
+        - cinder-tempest-plugin-lvm-lio-barbican-centos-8-stream:
             voting: false
         - cinder-tempest-plugin-lvm-tgt-barbican
         - nova-ceph-multistore:
@@ -181,9 +181,9 @@
         CINDER_ISCSI_HELPER: lioadm
 
 - job:
-    name: cinder-tempest-plugin-lvm-lio-barbican-centos-8
+    name: cinder-tempest-plugin-lvm-lio-barbican-centos-8-stream
     parent: cinder-tempest-plugin-lvm-lio-barbican
-    nodeset: devstack-single-node-centos-8
+    nodeset: devstack-single-node-centos-8-stream
     description: |
       This jobs configures Cinder with LVM, LIO, barbican and
       runs tempest tests and cinderlib tests on CentOS 8.