Removed deprecated method IOHelperTrait::isExpired()

Author: Geolim4

src/phpFastCache/Core/Pool/IO/IOHelperTrait.php

@@ -174,16 +174,6 @@ protected function encodeFilename($keyword)
         return md5($keyword);
     }
 
-    /**
-     * @return bool
-     */
-    public function isExpired()
-    {
-        trigger_error(__FUNCTION__ . '() is deprecated, use ExtendedCacheItemInterface::isExpired() instead.', E_USER_DEPRECATED);
-
-        return true;
-    }
-
     /**
      * @param $this ->config
      * @return int