feat: Add Secure Boot support to TPU v2alpha1 API (#98)

* feat: Add Secure Boot support to TPU v2alpha1 API

PiperOrigin-RevId: 474644226

Source-Link: googleapis/googleapis@f90b329

Source-Link: googleapis/googleapis-gen@4ad8763
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packages/google-cloud-tpu/protos/google/cloud/tpu/v2alpha1/cloud_tpu.proto

@@ -1,4 +1,4 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -448,6 +448,9 @@ message Node {
 
   // Output only. The Symptoms that have occurred to the TPU Node.
   repeated Symptom symptoms = 39 [(google.api.field_behavior) = OUTPUT_ONLY];
+
+  // Shielded Instance options.
+  ShieldedInstanceConfig shielded_instance_config = 45;
 }
 
 // Request for [ListNodes][google.cloud.tpu.v2alpha1.Tpu.ListNodes].
@@ -780,3 +783,9 @@ message GetGuestAttributesResponse {
   // The guest attributes for the TPU workers.
   repeated GuestAttributes guest_attributes = 1;
 }
+
+// A set of Shielded Instance options.
+message ShieldedInstanceConfig {
+  // Defines whether the instance has Secure Boot enabled.
+  bool enable_secure_boot = 1;
+}