Add panko metadata for memcache security strategy

Change-Id: Ib14a9f909aabf564a0f2820843d8c2619672afbb
Related-Prod: PROD-23561
diff --git a/panko/server/single.yml b/panko/server/single.yml
index 5e91db1..dd08349 100644
--- a/panko/server/single.yml
+++ b/panko/server/single.yml
@@ -31,3 +31,8 @@
         cron:
           minute: 0
           hour: 2
+      cache:
+        security:
+          enabled: ${_param:panko_memcache_security_enabled}
+          strategy: ${_param:openstack_memcache_security_strategy}
+          secret_key: ${_param:panko_memcache_secret_key}