Preload Files error

[yexiaodong]

Describe the bug
add preload.js error

To Reproduce
vue.config.js

background.js

npm run electron:build

Expected behavior

Screenshots

Environment (please complete the following information):

• custom config for vcp-electron-builder: none
• (if possible) link to your repo:
• terminal output from running vue info:

System:
OS: Windows 10 10.0.18363
CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
Binaries:
Node: 12.18.3 - D:\soft\nodejs\node.EXE
Yarn: 1.22.4 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
npm: 6.14.6 - D:\soft\nodejs\npm.CMD
Browsers:
Edge: 44.18362.449.0
npmPackages:
@vue/babel-helper-vue-jsx-merge-props: 1.0.0
@vue/babel-plugin-transform-vue-jsx: 1.0.0
@vue/babel-preset-app: 3.12.1
@vue/babel-preset-jsx: 1.1.1
@vue/babel-sugar-functional-vue: 1.0.0
@vue/babel-sugar-inject-h: 1.0.0
@vue/babel-sugar-v-model: 1.1.1
@vue/babel-sugar-v-on: 1.1.0
@vue/cli-overlay: 3.12.1
@vue/cli-plugin-babel: ^3.12.1 => 3.12.1
@vue/cli-plugin-eslint: ^3.12.1 => 3.12.1
@vue/cli-service: ^3.12.1 => 3.12.1
@vue/cli-shared-utils: 3.12.1
@vue/component-compiler-utils: 3.0.0
@vue/preload-webpack-plugin: 1.1.1
@vue/web-component-wrapper: 1.2.0
eslint-plugin-vue: ^5.2.3 => 5.2.3 (4.7.1)
vue: ^2.6.11 => 2.6.11
vue-cli-plugin-electron-builder: ~2.0.0-rc.4 => 2.0.0-rc.4
vue-eslint-parser: 5.0.0 (2.0.3)
vue-hot-reload-api: 2.3.4
vue-json-component: ^0.4.1 => 0.4.1
vue-lazyload: 1.2.3
vue-loader: 15.7.1
vue-markdown: ^2.2.4 => 2.2.4
vue-router: ^3.1.6 => 3.1.6
vue-style-loader: 4.1.2
vue-tabs-chrome: ^0.5.1 => 0.5.1
vue-template-compiler: ^2.6.11 => 2.6.11
vue-template-es2015-compiler: 1.9.1
vuex: ^3.2.0 => 3.2.0
npmGlobalPackages:
@vue/cli: Not Found
Additional context

[nklayman]

Preload support was not added to webpack until v4.33.0 (see webpack/webpack#9188). You will need to update your webpack version, deleting your package-lock.json and then running npm install should work.