Package Level Composer Not Triggered in Lumen Package Development

I'm trying to create a package to publish in packagist, for this I am using the package level composer.json to install the dependencies.

my package level composer.json is as follow

{
    "name": "my-company/my-package",
    "description": "Package Desciption",
    "authors": [
        {
            "name": "xxxxx",
            "email": "xxxxx@gmail.com"
        }
    ],
    "minimum-stability": "dev",
    "require": {
        "propaganistas/laravel-phone": "^4.1"
    }
}

I declare this on my main root autoload in composer.json as follow:

"autoload": {
        "classmap": [
            "database/seeds",
            "database/factories"
        ],
        "psr-4": {
            "App\\": "app/",
            "MyCompany\\MyPackage\\": "packages/my-company/my-package/"
        }
    },

when I run the composer install in the root composer.json the child composer.json is not triggered.

via Chebli Mohamed