Fix license

Signed-off-by: Rishabh Maurya <rishabhmaurya05@gmail.com>

Author: rishabhmaurya

modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.derived.txt

@@ -1,20 +1,9 @@
 #
-# Licensed to Elasticsearch under one or more contributor
-# license agreements. See the NOTICE file distributed with
-# this work for additional information regarding copyright
-# ownership. Elasticsearch 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
+# SPDX-License-Identifier: Apache-2.0
 #
-#    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.
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
 #
 
 # This file contains an allowlist for functions to be used in derived field context