Um, also let the "stack" user account use our file

Change-Id: I0518198ce11660864f9e0ffe872b29d741f85a00
diff --git a/roles/sp-openstack-integration-groups/tasks/main.yaml b/roles/sp-openstack-integration-groups/tasks/main.yaml
index 551cbb7..5738eb8 100644
--- a/roles/sp-openstack-integration-groups/tasks/main.yaml
+++ b/roles/sp-openstack-integration-groups/tasks/main.yaml
@@ -9,7 +9,7 @@
   become: true
   ansible.builtin.lineinfile:
     backrefs: true
-    line: "\\g<1>:cinder,nova,glance"
+    line: "\\g<1>:cinder,nova,glance,stack"
     path: /etc/group
     regexp: "^(spopenstack:[^:]*:[^:]*):$"