src: Client#readyAt should be updated when triggerReady is called (#3234)

src/client/websocket/WebSocketManager.js

@@ -424,8 +424,11 @@ class WebSocketManager {
       this.debug('Tried to mark self as ready, but already ready');
       return;
     }
+
     this.status = Status.READY;
 
+    this.client.readyAt = new Date();
+
     /**
      * Emitted when the client becomes ready to start working.
      * @event Client#ready