安裝html-webpack-plugin，引入報錯
cnpm install html-webpack-plugin --save-dev
const HtmlWebpackPlugin = require('html-webpack-plugin')? 報錯
錯誤提示：
module.js:550
? ? throw err;
? ? ^
Error: Cannot find module 'webpack-sources'
? ? at Function.Module._resolveFilename (module.js:548:15)
? ? at Function.Module._load (module.js:475:25)
? ? at Module.require (module.js:597:17)
? ? at require (D:\webpack-demo\node_modules\v8-compile-cache\v8-compile-cache.js:159:20)
? ? at Object.<anonymous> (D:\webpack-demo\node_modules\[email protected]@webpack\lib\javascript\CommonJsChunkFormatPlugin.js:8:26)
? ? at Module._compile (D:\webpack-demo\node_modules\v8-compile-cache\v8-compile-cache.js:192:30)
? ? at Object.Module._extensions..js (module.js:664:10)
? ? at Module.load (module.js:566:32)
? ? at tryModuleLoad (module.js:506:12)
? ? at Function.Module._load (module.js:498:3)
