Error: Cannot find module 'webpa

 "node": "^12.16.3",
 "npm": "^6.14.4",
 "webpack": "^5.8.0",
  "webpack-cli": "^4...",
  "webpack-dev-server": "^3.11.0"
之前的版本-------------------------   npm run dev 时候报错 Error: Cannot find module 'webpack/bin/config-yargs' 

原因是  "webpack-cli": "^4..." 和   "webpack-dev-server": "^3.11.0" 版本不兼容，
解决：降级webpack-cli  ,     npm install webpack-cli@3.3.12