Add copyright

Signed-off-by: Heng Qian <qianheng@amazon.com>

Author: qianheng-aws

opensearch/src/test/java/org/opensearch/sql/opensearch/request/AggregateAnalyzerTest.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
 package org.opensearch.sql.opensearch.request;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;