Add license header

modules/integration/tests-integration/tests-backend/src/test/java/org/wso2/identity/integration/test/oauth2/OAuth2TokenExchangeGrantTypeTestCase.java

@@ -1,3 +1,20 @@
+/*
+ * Copyright (c) 2023, WSO2 LLC. (http://www.wso2.com).
+ *
+ * WSO2 LLC. 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.
+ */
 package org.wso2.identity.integration.test.oauth2;
 
 import org.apache.commons.codec.binary.Base64;