refactor(cli-service): webpack devtool option (#5735)

Close: #5729

Author: jeneser

packages/@vue/cli-service/lib/commands/serve.js

@@ -51,7 +51,7 @@ module.exports = (api, options) => {
     api.chainWebpack(webpackConfig => {
       if (process.env.NODE_ENV !== 'production' && process.env.NODE_ENV !== 'test') {
         webpackConfig
-          .devtool('cheap-module-eval-source-map')
+          .devtool('eval-cheap-module-source-map')
 
         webpackConfig
           .plugin('hmr')