Status code must be an integer following psr-7

Author: snapshotpl

src/Response.php

@@ -174,8 +174,7 @@ public function withStatus($code, $reasonPhrase = '')
      */
     private function setStatusCode($code)
     {
-        if (! is_numeric($code)
-            || is_float($code)
+        if (! is_int($code)
             || $code < static::MIN_STATUS_CODE_VALUE
             || $code > static::MAX_STATUS_CODE_VALUE
         ) {

src/Response/Serializer.php

@@ -106,6 +106,6 @@ private static function getStatusLine(StreamInterface $stream)
             throw new UnexpectedValueException('No status line detected');
         }
 
-        return [$matches['version'], $matches['status'], isset($matches['reason']) ? $matches['reason'] : ''];
+        return [$matches['version'], (int) $matches['status'], isset($matches['reason']) ? $matches['reason'] : ''];
     }
 }

test/ResponseTest.php

@@ -78,7 +78,7 @@ public function ianaCodesReasonPhrasesProvider()
         $records = $xpath->query('//ns:record');
 
         foreach ($records as $record) {
-            $value = $xpath->query('.//ns:value', $record)->item(0)->nodeValue;
+            $value = (int) $xpath->query('.//ns:value', $record)->item(0)->nodeValue;
             $description = $xpath->query('.//ns:description', $record)->item(0)->nodeValue;
 
             if (in_array($description, ['Unassigned', '(Unused)'])) {
@@ -185,6 +185,7 @@ public function invalidStatusCodes()
             'too-high' => [600],
             'null' => [null],
             'string' => ['foo'],
+            'string-integer' => ['200'],
         ];
     }