Add lisence header

ballerina-tests/tests/76_number_types_pb.bal

@@ -1,3 +1,19 @@
+// Copyright (c) 2022 WSO2 LLC. (http://www.wso2.com) All Rights Reserved.
+//
+// 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.
+
 import ballerina/grpc;
 import ballerina/lang.'int;
 import ballerina/protobuf;