Update changelog

Author: maidmaid

src/Symfony/Component/Serializer/CHANGELOG.md

@@ -6,6 +6,8 @@ CHANGELOG
 
 * `AbstractNormalizer::handleCircularReference` is now final, and receives two optional extra arguments: the format and the context
 * added support for XML comment encoding (encoding `['#comment' => ' foo ']` results `<!-- foo -->`)
+* added optional `int[] $encoderIgnoredNodeTypes` argument to `XmlEncoder::__construct` to configure node types to be
+  ignored during encoding.
 
 4.1.0
 -----