message: fix(shell_automaton/testing): rpc_service not compiling
diff: // Copyright (c) SimpleStaking, Viable Systems and Tezedge Contributors
  // SPDX-License-Identifier: MIT
  +use serde::Serialize;
  +
  pub use shell_automaton::service::rpc_service::{
  RpcId, RpcRecvError, RpcRequest, RpcRequestStream, RpcService,
  };
  @@ -19,7 +21,10 @@ impl RpcService for RpcServiceDummy {
  Err(RpcRecvError::Empty)
  }
  - fn respond(&mut self, call_id: RpcId, json: serde_json::Value) {
  + fn respond<J>(&mut self, call_id: RpcId, json: J)
  + where
  + J: Serialize,
  + {
  let _ = (call_id, json);
  }
  