Update attribute_setter.py

Change copyright date

Author: CarolynRountree

core/src/main/python/wlsdeploy/tool/util/attribute_setter.py

@@ -1,5 +1,5 @@
 """
-Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
+Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
 The Universal Permissive License (UPL), Version 1.0
 """
 from sets import Set