Bump up ONOS to version 2.3.1 of yangtools

Change-Id: I96c3ce7672df6c11f9049eb8462b395b75087da2
diff --git a/apps/yang/src/main/java/org/onosproject/yang/impl/YangRuntimeManager.java b/apps/yang/src/main/java/org/onosproject/yang/impl/YangRuntimeManager.java
index 5d9a076..950a63e 100644
--- a/apps/yang/src/main/java/org/onosproject/yang/impl/YangRuntimeManager.java
+++ b/apps/yang/src/main/java/org/onosproject/yang/impl/YangRuntimeManager.java
@@ -163,6 +163,17 @@
     }
 
     @Override
+    public void registerAnydataSchema(Class id, Class id1) {
+        throw new UnsupportedOperationException("registerAnydataSchema() needs to be implemented");
+    }
+
+    @Override
+    public void unregisterAnydataSchema(Class id, Class id1) {
+        throw new UnsupportedOperationException("unregisterAnydataSchema() needs to be implemented");
+
+    }
+
+    @Override
     public SchemaContext getSchemaContext(ResourceId resourceId) {
         checkNotNull(resourceId, " resource id can't be null.");
         NodeKey key = resourceId.nodeKeys().get(0);