changes to NOTICE to conform to release policy (#15)

diff --git a/NOTICE.txt b/NOTICE.txt
index 419753d..beac922 100644
--- a/NOTICE.txt
+++ b/NOTICE.txt
@@ -1,16 +1,5 @@
 Apache OpenWhisk Intellij Plugin
+Copyright 2020-2021 The Apache Software Foundation
 
-Licensed to the Apache Software Foundation (ASF) under one or more
-contributor license agreements.  See the NOTICE file distributed with
-this work for additional information regarding copyright ownership.
-The ASF licenses this file 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.
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).