feat: expose display_name to batch v1 API

PiperOrigin-RevId: 573914933

google/cloud/batch/v1/task.proto

@@ -234,6 +234,12 @@ message Runnable {
     Barrier barrier = 6;
   }
 
+  // Optional. DisplayName is an optional field that can be provided by the
+  // caller. If provided, it will be used in logs and other outputs to identify
+  // the script, making it easier for users to understand the logs. If not
+  // provided the index of the runnable will be used for outputs.
+  string display_name = 10 [(google.api.field_behavior) = OPTIONAL];
+
   // Normally, a non-zero exit status causes the Task to fail. This flag allows
   // execution of other Runnables to continue instead.
   bool ignore_exit_status = 3;