SEBA-457 Upgrade to xos-core 2.2.5

Change-Id: I3871538dd47c94ce6e188d7be0ea3dad710904c0
diff --git a/Dockerfile.synchronizer b/Dockerfile.synchronizer
index fd58002..456c595 100644
--- a/Dockerfile.synchronizer
+++ b/Dockerfile.synchronizer
@@ -16,7 +16,7 @@
 
 # xosproject/volt-synchronizer
 
-FROM xosproject/xos-synchronizer-base:2.2.1
+FROM xosproject/xos-synchronizer-base:2.2.5
 
 COPY xos/synchronizer /opt/xos/synchronizers/volt
 COPY VERSION /opt/xos/synchronizers/volt/