composer.json

{
  "require-dev": {
    "vendor1/package1": "^1.0",
    "vendor1/package2": "^2.0"
  }
}
-----
{
  "require-dev": {
    "vendor1/package1": "^1.0",
    "vendor1/package2": "^2.0"
  },
  "require": {
    "vendor1/package3": "^3.0"
  }
}