Updated service to use new XOS core version: 2.1.22

Change-Id: Ia1b6632895014e7b5586eb81431cac5caf6b89c2
diff --git a/Dockerfile.synchronizer b/Dockerfile.synchronizer
index 5c838cc..3250c4d 100644
--- a/Dockerfile.synchronizer
+++ b/Dockerfile.synchronizer
@@ -16,7 +16,7 @@
 
 # xosproject/vtn-synchronizer
 
-FROM xosproject/xos-synchronizer-base:2.1.9
+FROM xosproject/xos-synchronizer-base:2.1.22
 
 COPY xos/synchronizer /opt/xos/synchronizers/vtn
 COPY VERSION /opt/xos/synchronizers/vtn/