acknowledge Basho license on ORSet code (#435)

distributed-data/src/main/scala/org/apache/pekko/cluster/ddata/ORSet.scala

@@ -11,6 +11,24 @@
  * Copyright (C) 2009-2022 Lightbend Inc. <https://www.lightbend.com>
  */
 
+/*
+ * Copyright (c) 2007-2013 Basho Technologies, Inc.  All Rights Reserved.
+ *
+ * This file is provided to you under the Apache License,
+ * Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License.  You may obtain
+ * a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
 package org.apache.pekko.cluster.ddata
 
 import scala.annotation.tailrec