ensitech-273 fix deprecated

Author: C0rTeZ13

src/Events/Audited.php

@@ -36,7 +36,7 @@ class Audited
      * @param \Ensi\LaravelAuditing\Contracts\AuditDriver $driver
      * @param \Ensi\LaravelAuditing\Contracts\Audit       $audit
      */
-    public function __construct(Auditable $model, AuditDriver $driver, Audit $audit = null)
+    public function __construct(Auditable $model, AuditDriver $driver, ?Audit $audit = null)
     {
         $this->model = $model;
         $this->driver = $driver;

src/Exceptions/AuditableTransitionException.php

@@ -16,7 +16,7 @@ class AuditableTransitionException extends AuditingException
     /**
      * {@inheritdoc}
      */
-    public function __construct($message = '', array $incompatibilities = [], $code = 0, Throwable $previous = null)
+    public function __construct($message = '', array $incompatibilities = [], $code = 0, ?Throwable $previous = null)
     {
         parent::__construct($message, $code, $previous);