打包遇到无法访问外网资源，直接配置国内镜像地址

直接加入如下代码就行：

{
  "builder": {
    "gc": {
      "defaultKeepStorage": "20GB",
      "enabled": true
    }
  },
  "experimental": false,
  "registry-mirrors": [
    "https://daocloud.io",
    "https://hub.xdark.top",
    "https://hub.littlediary.cn",
    "https://dockerpull.org"
  ]
}