webpack启动时，cesium的buildModuleUrl.js产生3个警告：require cannot be statically extracted

vue工程使用webpack，增加了cesium依赖，启动时会输出下面的警告信息：

 WARNING  Compiled with 3 warnings                                                                                                             4:26:41 PM
 warning  in ./node_modules/cesium/Source/Core/buildModuleUrl.js
114:14-21 Critical dependency: require function is used in a way in which dependencies cannot be statically extracted
 warning  in ./node_modules/cesium/Source/Core/buildModuleUrl.js
52:12-19 Critical dependency: require function is used in a way in which dependencies cannot be statically extracted
 warning  in ./node_modules/cesium/Source/Core/buildModuleUrl.js
80:25-32 Critical dependency: require function is used in a way in which dependencies cannot be statically extracted

解决办法是修改webpack.base.conf.js，如果是vue-cli工程则是修改vue.config.js，增加如下的内容：

{
  module: {
    unknownContextRegExp = /^('|')\.\/.*?\1$/
    unknownContextCritical = false
  },
  amd: {
    toUrlUndefined: true
  }
}

参考地址： https://github.com/CesiumGS/cesium/issues/9790