Moving DHCP event handling in model policy, update the subscriber only when needed

Change-Id: I77ec7c05d802a5902d96a8216b932d7a703af4e9
diff --git a/Dockerfile.synchronizer b/Dockerfile.synchronizer
index 9de15c9..536e006 100644
--- a/Dockerfile.synchronizer
+++ b/Dockerfile.synchronizer
@@ -16,7 +16,7 @@
 
 # xosproject/att-workflow-driver-synchronizer
 
-FROM xosproject/xos-synchronizer-base:2.1.12
+FROM xosproject/xos-synchronizer-base:2.1.19
 
 COPY xos/synchronizer /opt/xos/synchronizers/att-workflow-driver
 COPY VERSION /opt/xos/synchronizers/att-workflow-driver/