Update to latest PHPStan and PHPCSFixer

phpstan.neon

@@ -5,9 +5,4 @@ parameters:
 	paths:
 		- src
 		- tests
-	ignoreErrors:
-		-
-			message: '#::seek\(\) has no return type specified.#'
-			paths:
-				- src/*
 

src/Base64Stream.php

@@ -146,7 +146,6 @@ private function fillBuffer(int $length) : void
      * encoded data and is not supported.
      *
      * @param int $length
-     * @return string
      */
     public function read($length) : string
     {

src/CharsetStream.php

@@ -144,7 +144,6 @@ public function eof() : bool
      * them after converting to the target string charset.
      *
      * @param int $length
-     * @return string
      */
     public function read($length) : string
     {

src/NonClosingStream.php

@@ -51,7 +51,7 @@ class NonClosingStream implements StreamInterface
      */
     public function close() : void
     {
-        $this->stream = null;
+        $this->stream = null;	// @phpstan-ignore-line
     }
 
     /**
@@ -61,7 +61,7 @@ public function close() : void
      */
     public function detach()
     {
-        $this->stream = null;
+        $this->stream = null;	// @phpstan-ignore-line
 
         return null;
     }

src/PregReplaceFilterStream.php

@@ -101,7 +101,6 @@ private function fillBuffer(int $length) : void
      * bytes.
      *
      * @param int $length
-     * @return string
      */
     public function read($length) : string
     {

src/SeekingLimitStream.php

@@ -178,7 +178,6 @@ public function seekAndRead(int $length) : string
      * 'seeked' back to its position prior to the call to read().
      *
      * @param int $length
-     * @return string
      */
     public function read($length) : string
     {