报错信息如下

ERROR in ./src/login.vue
Module Error (from ./node_modules/vue-loader/lib/index.js):
vue-loader was used without the corresponding plugin. Make sure to include VueLoaderPlugin in your webpack config.
 @ ./src/main.js 7:13-35

ERROR in ./src/login.vue?vue&type=template&id=19e76240& 2:0
Module parse failed: Unexpected token (2:0)
File was processed with these loaders:
 * ./node_modules/vue-loader/lib/index.js
You may need an additional loader to handle the result of these loaders.

原因

参考官方文档
https://vue-loader.vuejs.org/migrating.html#a-plugin-is-now-required

解决办法如下

// webpack.config.js
const VueLoaderPlugin = require('vue-loader/lib/plugin')

module.exports = {
  // ...
  plugins: [
    new VueLoaderPlugin()
  ]
}