Use json_encode with option JSON_UNESCAPED_SLASHES

When encoding JSON, use option JSON_UNESCAPED_SLASHES which allows to
disable a non-standard unnecessary over-encoding of '/' as '\/' by json_encode.

This option of json_encode is available on PHP 5.4+.

Author: dolmen

composer.json

@@ -20,7 +20,7 @@
     ],
     "license": "BSD-3-Clause",
     "require": {
-        "php": ">=5.3.0"
+        "php": ">=5.4.0"
     },
     "autoload": {
         "psr-4": {

src/JWT.php

@@ -314,7 +314,7 @@ public static function jsonDecode($input)
      */
     public static function jsonEncode($input)
     {
-        $json = \json_encode($input);
+        $json = \json_encode($input, JSON_UNESCAPED_SLASHES);
         if ($errno = \json_last_error()) {
             static::handleJsonError($errno);
         } elseif ($json === 'null' && $input !== null) {