错误提示如下：

BREAKING CHANGE: It's no longer allowed to omit the '-loader' suffix when using loaders.
                 You need to specify 'json-loader' instead of 'json',
                 see https://webpack.js.org/guides/migrating/#automatic-loader-module-name-extension-removed

Webpack新版本要求配置module中的loader不能缩写，也就是loader:"json-loader"中的-loader必须要写

类似的还有loader:"vue-loader"