Add missing license headers

components/device-mgt-extensions/io.entgra.device.mgt.core.device.mgt.extensions.push.notification.provider.fcm/src/main/java/io/entgra/device/mgt/core/device/mgt/extensions/push/notification/provider/fcm/util/FCMUtil.java

@@ -1,3 +1,20 @@
+/*
+ * Copyright (c) 2018 - 2024, Entgra (Pvt) Ltd. (http://www.entgra.io) All Rights Reserved.
+ *
+ * Entgra (Pvt) Ltd. 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 io.entgra.device.mgt.core.device.mgt.extensions.push.notification.provider.fcm.util;
 
 import com.google.auth.oauth2.GoogleCredentials;

components/device-mgt/io.entgra.device.mgt.core.device.mgt.core/src/main/java/io/entgra/device/mgt/core/device/mgt/core/config/push/notification/ContextMetadata.java

@@ -1,3 +1,20 @@
+/*
+ * Copyright (c) 2018 - 2023, Entgra (Pvt) Ltd. (http://www.entgra.io) All Rights Reserved.
+ *
+ * Entgra (Pvt) Ltd. 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 io.entgra.device.mgt.core.device.mgt.core.config.push.notification;
 
 import javax.xml.bind.annotation.XmlAttribute;