Merge branch '2.x' into 3.0

* 2.x:
  update changelog

Author: xabbuh

CHANGELOG.md

@@ -124,6 +124,7 @@ CHANGELOG
 2.8.1
 -----
 
+* fixed handling requests without a content type inside the `RequestBodyParamConverter`
 * `FlattenExceptionNormalizer` does no longer implement the `CacheableSupportsMethodInterface` to
   ensure compatibility with older versions of the Symfony Serializer component