Feat multiple providers

[gaetan-hexadog]

This PR adds the possibility to declare multiple publishable providers. It's useful when the package need to publish and register multiple providers (like a standard ServiceProvider + an AuthServiceProvider).

It can be used with the already existing method publishesServiceProvider but by providing and array of providers name

$package
    ->name('your-package-name')
    ->publishesServiceProvider([
        $nameOfYourServiceProvider1,
        $nameOfYourServiceProvider2,
        ...
    ]);