Add version directive

Author: alexander-schranz

components/http_foundation.rst

@@ -634,6 +634,8 @@ represented by a PHP callable instead of a string::
 Streaming a JSON Response
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
+.. versionadded:: 6.2
+
 The :class:`Symfony\\Component\\HttpFoundation\\StreamedJsonResponse` class allows
 an API to return a lot of data as JSON and keep the used resources low by make usage
 of Generators.