feat: upgrade css-loader to 1.0

lib/builder/webpack/utils/postcss.js

@@ -9,6 +9,7 @@ import { isPureObject } from '../../../common/utils'
 export default class PostcssConfig {
   constructor(options, nuxt) {
     this.nuxt = nuxt
+    this.dev = options.dev
     this.postcss = options.build.postcss
     this.srcDir = options.srcDir
     this.rootDir = options.rootDir
@@ -45,7 +46,8 @@ export default class PostcssConfig {
         'postcss-preset-env': {
           // https://cssdb.org/#staging-process
           stage: 2
-        }
+        },
+        'cssnano': !this.dev
       }
     }
   }

lib/builder/webpack/utils/style-loader.js

@@ -73,7 +73,6 @@ export default class StyleLoader {
       loader: (this.isServer && this.extractCSS) ? 'css-loader/locals' : 'css-loader',
       options: Object.assign({
         sourceMap: this.sourceMap,
-        minimize: !this.dev,
         importLoaders: importLoaders,
         alias: cssLoaderAlias
       }, options)

package.json

@@ -81,7 +81,8 @@
     "compression": "^1.7.1",
     "connect": "^3.6.5",
     "consola": "^1.4.1",
-    "css-loader": "^0.28.11",
+    "css-loader": "^1.0.0",
+    "cssnano": "^4.0.5",
     "es6-promise": "^4.2.4",
     "esm": "^3.0.62",
     "etag": "^1.8.1",