Drop laravel elixir, we’ll use nginx’s etag feature for cache-ing

package.json

@@ -6,8 +6,8 @@
   "devDependencies": {
     "gulp": "~3.9",
     "gulp-brotli": "^1.0.1",
+    "gulp-sass": "^2.3.2",
     "gulp-zopfli": "^1.0.0",
-    "laravel-elixir": "^6.0.0-2",
     "lint-staged": "^1.0.1",
     "pre-commit": "^1.1.3",
     "stylelint": "^6.6.0",
@@ -15,8 +15,6 @@
   },
   "private": true,
   "scripts": {
-    "prod": "gulp --production",
-    "dev": "gulp watch",
     "lint-staged": "lint-staged",
     "stylelint-staged": "stylelint --syntax=scss"
   },