'implementation' => OwenItAuditingModelsAudit::class,

'user' => [
    'primary_key' => 'id',
    'foreign_key' => 'variant_id',
    'model'       => AppVariant::class,
    'resolver'    => AppVariant::class,
],

use OwenItAuditingAuditable;
use OwenItAuditingContractsAuditable as AuditableContract;

class Variant extends BaseModel implements AuditableContract{

   use Auditable;
 --------Code here----------------
}

UnexpectedValueException
 Invalid User resolver, callable or UserResolver FQCN expected