adjust to latest cs fixer rules

Author: dbu

spec/Encoding/MemoryStream.php

@@ -103,7 +103,7 @@ public function getContents(): string
         return $this->read($this->size);
     }
 
-    public function getMetadata(string $key = null)
+    public function getMetadata(?string $key = null)
     {
         $metadata = stream_get_meta_data($this->resource);
 

src/Authentication/Matching.php

@@ -27,7 +27,7 @@ final class Matching implements Authentication
      */
     private $matcher;
 
-    public function __construct(Authentication $authentication, callable $matcher = null)
+    public function __construct(Authentication $authentication, ?callable $matcher = null)
     {
         if (is_null($matcher)) {
             $matcher = function () {

src/Cookie.php

@@ -73,7 +73,7 @@ public function __construct(
         $path = null,
         $secure = false,
         $httpOnly = false,
-        \DateTime $expires = null
+        ?\DateTime $expires = null
     ) {
         $this->validateName($name);
         $this->validateValue($value);
@@ -109,7 +109,7 @@ public static function createWithoutValidation(
         $path = null,
         $secure = false,
         $httpOnly = false,
-        \DateTime $expires = null
+        ?\DateTime $expires = null
     ) {
         $cookie = new self('name', null, null, $domain, $path, $secure, $httpOnly, $expires);
         $cookie->name = $name;
@@ -228,7 +228,7 @@ public function hasExpires()
      *
      * @return Cookie
      */
-    public function withExpires(\DateTime $expires = null)
+    public function withExpires(?\DateTime $expires = null)
     {
         $new = clone $this;
         $new->expires = $expires;

src/Decorator/StreamDecorator.php

@@ -86,10 +86,7 @@ public function getContents(): string
         return $this->stream->getContents();
     }
 
-    /**
-     * @return mixed
-     */
-    public function getMetadata(string $key = null)
+    public function getMetadata(?string $key = null)
     {
         return $this->stream->getMetadata($key);
     }

src/Stream/BufferedStream.php

@@ -209,7 +209,7 @@ public function getContents(): string
         return $read;
     }
 
-    public function getMetadata(string $key = null)
+    public function getMetadata(?string $key = null)
     {
         if (null === $this->resource) {
             if (null === $key) {