补充：解决Ubuntu20.04.4安装KRS时无法下载github代码问题

官方代码下载自github（gitlab），如何访问外网的问题这里可以合法合规解决，就是先把github的代码导入gitee，再采取同步的方式解决：

原代码段如下：仔细看代码内容，链接路径全为github。

cat << 'EOF' > krs_rolling.repos
repositories:
  ros2/ament_lint:
    type: git
    url: https://github.com/ament/ament_lint
    version: master
  ros2/launch:
    type: git
    url: https://github.com/ros2/launch
    version: master
  ros2/gazebo_ros_pkgs:
    type: git
    url: https://github.com/ros-simulation/gazebo_ros_pkgs
    version: da14a69e79502cd08064ccd261366ff023a9162a
 
  perception/image_common:
    type: git
    url: https://github.com/ros-perception/image_common
    version: 9729de81f7dff6156f644d6152b200f687360f1f
  perception/image_pipeline:
    type: git
    url: https://github.com/ros-acceleration/image_pipeline
    version: beta
  perception/vision_opencv:
    type: git
    url: https://github.com/ros-perception/vision_opencv
    version: 7bbc5ecc232e8faf36b45efa