Upgrade laravel-mix to 0.8.3

package.json

@@ -12,7 +12,7 @@
     "bootstrap-sass": "^3.3.7",
     "cross-env": "^3.2.3",
     "jquery": "^3.1.1",
-    "laravel-mix": "^0.8.1",
+    "laravel-mix": "^0.8.3",
     "lodash": "^4.17.4",
     "vue": "^2.1.10"
   }