package.json

{
  "devDependencies": {
    "gulp": "4.0.0",
    "gulp-uglify": "3.0.1",
    "gulp-concat": "2.6.1",
    "gulp-clean-css": "4.0.0",
    "gulp-inject": "5.0.2",
    "merge-stream": "^1.0.1"
  }
}