chore: add import for empty.proto

Google APIs · copybara-github · commit e3abc066b0dc · 2023-02-09T13:04:52.000-08:00
PiperOrigin-RevId: 508454292
diff --git a/google/cloud/tpu/v2/cloud_tpu.proto b/google/cloud/tpu/v2/cloud_tpu.proto
@@ -21,6 +21,7 @@ import "google/api/client.proto";
 import "google/api/field_behavior.proto";
 import "google/api/resource.proto";
 import "google/longrunning/operations.proto";
+import "google/protobuf/empty.proto";
 import "google/protobuf/field_mask.proto";
 import "google/protobuf/timestamp.proto";
 
