master branch 执行 example/sale 报 TypeError: Cannot read property 'properties' of undefined

### Description

master分支 example 执行npm run dev 无法启动

报错 ：
page-skeleton-webpack-plugin/examples/sale/node_modules/_webpack-cli@2.1.5@webpack-cli/bin/config-yargs.js:89
describe: optionsSchema.definitions.output.properties.path.description,
TypeError: Cannot read property 'properties' of undefined

### Steps to reproduce

1. cd example
2. npm install
3. npm run dev