Merge "doc: move to train in quickstart"

doc/source/user/quickstart.rst

@@ -400,15 +400,15 @@ There are a few options that are required to deploy Kolla-Ansible:
      kolla_install_type: "source"
 
   To use DockerHub images, the default image tag has to be overridden. Images are
-  tagged with release names. For example to use stable Rocky images set
+  tagged with release names. For example to use stable Train images set
 
   .. code-block:: console
 
-     openstack_release: "rocky"
+     openstack_release: "train"
 
   It's important to use same version of images as kolla-ansible. That
   means if pip was used to install kolla-ansible, that means it's latest stable
-  version so ``openstack_release`` should be set to rocky. If git was used with
+  version so ``openstack_release`` should be set to train. If git was used with
   master branch, DockerHub also provides daily builds of master branch (which is
   tagged as ``master``):