Add RootStackName parameter on stack update

The task to add the RootStackName parameter to plan-environment.yaml in
the plan was only in the create_deployment_plan workflow. This patch
also adds it to the update_deployment_plan workflow so that the
parameter will be present in the environment for both stack create and
update.

Change-Id: I560eaff21c22d2ab70c657b35a3d43a76003e6ba
Closes-Bug: #1853362

releasenotes/notes/add-rootstackname-on-update-258dbf091fea497e.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - The RootStackName parameter is now added to the plan in
+    plan-environment.yaml on both stack create and update. Previously it was
+    only added on create.

workbooks/plan_management.yaml

@@ -280,9 +280,22 @@ workflows:
 
       ensure_passwords_exist:
         action: tripleo.parameters.generate_passwords container=<% $.container %>
-        on-success: container_images_prepare
+        on-success: add_root_stack_name
         on-error: ensure_passwords_exist_set_status_failed
 
+      add_root_stack_name:
+        action: tripleo.parameters.update
+        input:
+          container: <% $.container %>
+          validate: <% $.validate_stack %>
+          parameters:
+            RootStackName: <% $.container %>
+        on-success: container_images_prepare
+        publish-on-error:
+          status: FAILED
+          message: <% task().result %>
+        on-error: send_message
+
       container_images_prepare:
         description: >
           Populate all container image parameters with default values.