[CORD-2889]
Use premade `postgres` container

Change-Id: Ifc9a021c425d8f03c98d566978400884fbace4de
diff --git a/xos-core/values.yaml b/xos-core/values.yaml
index 8f37704..ccb647c 100644
--- a/xos-core/values.yaml
+++ b/xos-core/values.yaml
@@ -24,8 +24,8 @@
     tag: 'master'
     pullPolicy: 'IfNotPresent'
   xos_db:
-    repository: xosproject/xos-postgres
-    tag: 'master'
+    repository: postgres
+    tag: '10.3-alpine'
     pullPolicy: 'IfNotPresent'
   xos_tosca:
     repository: xosproject/xos-tosca