Update README.md to include usb_port parameter in serial_to_pcl_node command

README.md

@@ -122,7 +122,7 @@ Make sure to connect the **SCL** and **SDA** lines for I2C communication, as wel
 ## How It Works
    - 
    ```bash
-   ros2 run serial_to_pcl serial_to_pcl_node
+   ros2 run serial_to_pcl serial_to_pcl_node --ros-args -p usb_port:=<Your_USB_port>
    ```
 ### Sensor Configuration