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,
        ...
    ]);

[spatie-bot]

Dear contributor,

because this pull request seems to be inactive for quite some time now, I've automatically closed it. If you feel this pull request deserves some attention from my human colleagues feel free to reopen it.