fs050: upgrade the undercloud to Podman containers

For the containerized undercloud upgrade job, make it so during the
upgrade from Rocky, the undercloud is upgrades to Stein with Podman
containers and not Docker anymore.

Depends-On: I6831b4b952c95fde31febf8e14cb27cf22ff859b
Change-Id: I539fe73f6d82156b045fa0d45aad9529e98c0c2e

config/general_config/featureset050.yml

@@ -23,3 +23,10 @@ run_tempest: false
 # configured public-vip and admin-vip.
 undercloud_generate_service_certificate: true
 undercloud_enable_swift_encryption: true
+
+undercloud_container_cli: >-
+  {% if release in ['rocky'] -%}
+  docker
+  {%- else -%}
+  podman
+  {%- endif -%}