Removed deprecation in YAML component

src/Symfony/Component/Yaml/Unescaper.php

@@ -19,15 +19,6 @@ namespace Symfony\Component\Yaml;
  */
 class Unescaper
 {
-    /**
-     * Parser and Inline assume UTF-8 encoding, so escaped Unicode characters
-     * must be converted to that encoding.
-     *
-     * @deprecated since version 2.5, to be removed in 3.0
-     * @internal
-     */
-    const ENCODING = 'UTF-8';
-
     /**
      * Regex fragment that matches an escaped character in a double quoted string.
      */