Update Heat template for environment

* update docker_ee_url default value
* always cache ucp images

Related-Prod: PRODX-39329
Change-Id: Ifb8f075d3148fa3421f99437284c8c781cb91180
diff --git a/de/heat-templates/multirack.yaml b/de/heat-templates/multirack.yaml
index 72520d2..fcde637 100644
--- a/de/heat-templates/multirack.yaml
+++ b/de/heat-templates/multirack.yaml
@@ -124,7 +124,7 @@
     default: 'system.compact.openstack.control'
   docker_ee_url:
     type: string
-    default: 'https://storebits.docker.com/ubuntu'
+    default: 'https://repos.mirantis.com/ubuntu'
   docker_ee_release:
     type: string
     default: 'stable-19.03'