fixed link to wiki page

the wiki page seems to have been renamed but the link to it hadn't

Author: t-schroeder

src/phpFastCache/Core/Pool/CacheItemPoolTrait.php

@@ -70,7 +70,7 @@ public function getItem($key)
              */
             if (!isset($this->itemInstances[ $key ])) {
                 if (preg_match('~([' . preg_quote(self::$unsupportedKeyChars, '~') . ']+)~', $key, $matches)) {
-                    throw new phpFastCacheInvalidArgumentException('Unsupported key character detected: "' . $matches[ 1 ] . '". Please check: https://github.com/PHPSocialNetwork/phpfastcache/wiki/%5BV6%5D-Unsupported-characters-in-key-identifiers');
+                    throw new phpFastCacheInvalidArgumentException('Unsupported key character detected: "' . $matches[ 1 ] . '". Please check: https://github.com/PHPSocialNetwork/phpfastcache/wiki/%5BV6%CB%96%5D-Unsupported-characters-in-key-identifiers');
                 }
 
                 /**
@@ -413,4 +413,4 @@ public function commit()
 
         return (bool)$return;
     }
-}
+}