style: fix (updated) code style

Author: JaZo

src/Client.php

@@ -18,7 +18,7 @@ class Client extends MockClient
      * @param \Swis\Http\Fixture\ResponseBuilderInterface $fixtureResponseBuilder
      * @param \Http\Message\ResponseFactory|null          $responseFactory
      */
-    public function __construct(ResponseBuilderInterface $fixtureResponseBuilder, ResponseFactory $responseFactory = null)
+    public function __construct(ResponseBuilderInterface $fixtureResponseBuilder, ?ResponseFactory $responseFactory = null)
     {
         parent::__construct($responseFactory);
 

src/MockNotFoundException.php

@@ -15,7 +15,7 @@ class MockNotFoundException extends \Exception
      * @param int             $code
      * @param \Throwable|null $previous
      */
-    public function __construct(string $message = '', array $possiblePaths = [], int $code = 0, \Throwable $previous = null)
+    public function __construct(string $message = '', array $possiblePaths = [], int $code = 0, ?\Throwable $previous = null)
     {
         $this->possiblePaths = $possiblePaths;
 

src/ResponseBuilder.php

@@ -64,8 +64,8 @@ class ResponseBuilder implements ResponseBuilderInterface
      */
     public function __construct(
         string $fixturesPath,
-        ResponseFactoryInterface $responseFactory = null,
-        StreamFactoryInterface $streamFactory = null
+        ?ResponseFactoryInterface $responseFactory = null,
+        ?StreamFactoryInterface $streamFactory = null
     ) {
         $this->fixturesPath = $fixturesPath;
         $this->responseFactory = $responseFactory ?: Psr17FactoryDiscovery::findResponseFactory();