Added license boilerplate to subnet yaml data in tests

tests/modules/net_vpc/fixture/data/factory-subnet.yaml

@@ -1,3 +1,17 @@
+# Copyright 2021 Google LLC
+# 
+# Licensed 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.
+
 region: europe-west1              
 description: Sample description   
 ip_cidr_range: 10.128.0.0/24