fix: Use NODE_ENV to determine if webpack should use production build instead of mode (#114)

Author: hmillison

lib/webpack.js

@@ -11,7 +11,7 @@ exports.chainWebpack = (webpackConfig) => {
   const target = process.env.VUE_CLI_SSR_TARGET
   if (!target) return
   const isClient = target === 'client'
-  const isProd = process.env.VUE_CLI_MODE === 'production'
+  const isProd = process.env.NODE_ENV === 'production'
 
   // Remove unneeded plugins
   webpackConfig.plugins.delete('hmr')