Generate `testbench.yaml` using Symfony Yaml

```php
use Symfony\Component\Yaml\Yaml;
use Workbench\App\Providers\WorkbenchServiceProvider;

$array = array_filter([
  "providers" => [WorkbenchServiceProvider::class],
  "migrations" => null,
  "workbench" => ["discovers" => ["web" => false]]
]);

$dump = Yaml::dump($array, 3, flags: Yaml::DUMP_NULL_AS_TILDE);

var_dump($dump);
```