guest: shutdown_runner: Add license header

Bug: none
Test: build
Change-Id: I0b797a1586936f60c3cefb7e8deff604342ff340
diff --git a/guest/shutdown_runner/src/main.rs b/guest/shutdown_runner/src/main.rs
index 19e9883..aee5915 100644
--- a/guest/shutdown_runner/src/main.rs
+++ b/guest/shutdown_runner/src/main.rs
@@ -1,3 +1,17 @@
+// Copyright 2024 The Android Open Source Project
+//
+// 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.
+
 use api::debian_service_client::DebianServiceClient;
 use api::ShutdownQueueOpeningRequest;
 use std::process::Command;