Add missing license header

Author: danischm

internal/provider/provider_test.go

@@ -1,3 +1,20 @@
+// Copyright © 2023 Cisco Systems, Inc. and its affiliates.
+// All rights reserved.
+//
+// Licensed under the Mozilla Public 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
+//
+//     https://mozilla.org/MPL/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.
+//
+// SPDX-License-Identifier: MPL-2.0
+
 package provider
 
 import (