Revert "Add autoprefix to postcss"

This reverts commit 509af1a0c3.

webpack.prod.js

@@ -13,12 +13,12 @@ module.exports = merge(common, {
         rules: [
             {
                 test: /\.css$/i,
-                use: ["style-loader", "css-loader", "postcss-loader"]
+                use: ["style-loader", "css-loader"]
             },
             {
                 test: /\.(png|jpg|gif)$/i,
                 use: ["file-loader"]
             }
         ]
-    }
+    },
 });