Using multiple versions of the same package in a project: package.json

package.json

{
  "name": "multiple-versions-of-package-in-project",
  "version": "1.0.0",
  "description": "Using multiple versions of the same package in a project",
  "main": "index.js",
  "scripts": {
    "start": "node index.js"
  },
  "keywords": [],
  "author": "Will Mendes <willmendesneto@gmail.com>",
  "license": "ISC",
  "dependencies": {
    "feature-toggle-service": "npm:feature-toggle-service@^4.0.0",
    "feature-toggle-service-next": "npm:feature-toggle-service@^6.0.0"
  }
}