chore(package): update laravel-mix to version 5.0.4

Closes #65

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "eslint-plugin-unicorn": "^9.1.1",
     "eslint-plugin-varspacing": "^1.2.1",
     "eslint-plugin-vue": "^5.2.3",
-    "laravel-mix": "^4.0.16",
+    "laravel-mix": "^5.0.4",
     "node-sass": "^4.12.0",
     "offline-plugin": "^5.0.7",
     "pre-commit": "^1.2.2",