Merge "Run TripleO jobs on CentOS8 instead of CentOS7" into stable/train

zuul.d/layout.yaml

@@ -22,15 +22,15 @@
       - tripleo-upgrades-train-pipeline
     check:
       jobs:
-        - tripleo-ci-centos-7-content-provider
-        - tripleo-ci-centos-7-scenario007-multinode-oooq-container:
+        - tripleo-ci-centos-8-content-provider
+        - tripleo-ci-centos-8-scenario007-multinode-oooq-container:
             vars:
               consumer_job: true
               build_container_images: false
               remove_tags:
                 - build
             dependencies:
-              - tripleo-ci-centos-7-content-provider
+              - tripleo-ci-centos-8-content-provider
             files:
               - ^manifests/profile/pacemaker/ovn.*$
               - ^manifests/profile/(base|pacemaker)/neutron/plugins/ml2/ovn.*$