message: fix(ci): pass make check-cargotoml
diff: @@ -6,6 +6,7 @@ use ckb_types::{
  };
  use crossbeam_channel::{bounded, select, Receiver, RecvError, Sender};
  use serde::{Deserialize, Serialize};
  +use serde_json::to_string;
  use std::collections::HashMap;
  use std::process::Command;
  use std::thread;
  @@ -112,8 +113,7 @@ impl NotifyService {
  // notify script
  if let Some(script) = self.config.new_block_notify_script.as_ref() {
  let block_json: ckb_jsonrpc_types::BlockView = block.into();
  - let args =
  - [serde_json::to_string(&block_json).expect("serializing should be ok")];
  + let args = [to_string(&block_json).expect("serializing should be ok")];
  if let Err(err) = Command::new(script).args(&args).status() {
  error!(
  "failed to run new_block_notify_script script, error: {}",
  