Fix issues reported by Style CI

Author: tspencer244

src/Exceptions/CouldNotSendNotification.php

@@ -9,19 +9,19 @@ class CouldNotSendNotification extends \Exception
     private $response;
 
     /**
-     * @param Response $response
-     * @param string $message
-     * @param int|null $code
+     * @param  Response  $response
+     * @param  string  $message
+     * @param  int|null  $code
      */
-    public function __construct(Response $response, string $message, int $code = null)
+    public function __construct(Response $response, string $message, ?int $code = null)
     {
         parent::__construct($message, $code ?? $response->getStatusCode());
 
         $this->response = $response;
     }
 
     /**
-     * @param Response $response
+     * @param  Response  $response
      * @return self
      */
     public static function serviceRespondedWithAnError(Response $response)