Merge branch '4.3' into 4.4

* 4.3:
  Add docs for DateTimeZoneNormalizer

Author: javiereguiluz

components/serializer.rst

@@ -737,6 +737,14 @@ There are several types of normalizers available:
     :phpclass:`DateTime` and :phpclass:`DateTimeImmutable`) into strings.
     By default, it uses the `RFC3339`_ format.
 
+:class:`Symfony\\Component\\Serializer\\Normalizer\\DateTimeZoneNormalizer`
+    This normalizer converts :phpclass:`DateTimeZone` objects into strings that
+    represent the name of the timezone according to the `list of PHP timezones`_.
+
+    .. versionadded:: 4.3
+
+        The ``DateTimeZoneNormalizer`` was introduced in Symfony 4.3.
+
 :class:`Symfony\\Component\\Serializer\\Normalizer\\DataUriNormalizer`
     This normalizer converts :phpclass:`SplFileInfo` objects into a data URI
     string (``data:...``) such that files can be embedded into serialized data.
@@ -1500,3 +1508,4 @@ Learn more
 .. _`RFC 7807`: https://tools.ietf.org/html/rfc7807
 .. _`Value Objects`: https://en.wikipedia.org/wiki/Value_object
 .. _`API Platform`: https://api-platform.com
+.. _`list of PHP timezones`: https://www.php.net/manual/en/timezones.php

serializer.rst

@@ -61,13 +61,19 @@ As well as the following normalizers:
   handle typical data objects
 * :class:`Symfony\\Component\\Serializer\\Normalizer\\DateTimeNormalizer` for
   objects implementing the :phpclass:`DateTimeInterface` interface
+* :class:`Symfony\\Component\\Serializer\\Normalizer\\DateTimeZoneNormalizer` for
+  :phpclass:`DateTimeZone` objects
 * :class:`Symfony\\Component\\Serializer\\Normalizer\\DataUriNormalizer` to
   transform :phpclass:`SplFileInfo` objects in `Data URIs`_
 * :class:`Symfony\\Component\\Serializer\\Normalizer\\JsonSerializableNormalizer`
   to deal with objects implementing the :phpclass:`JsonSerializable` interface
 * :class:`Symfony\\Component\\Serializer\\Normalizer\\ArrayDenormalizer` to
   denormalize arrays of objects using a format like `MyObject[]` (note the `[]` suffix)
 
+.. versionadded:: 4.3
+
+    The ``DateTimeZoneNormalizer`` was introduced in Symfony 4.3.
+
 Custom normalizers and/or encoders can also be loaded by tagging them as
 :ref:`serializer.normalizer <reference-dic-tags-serializer-normalizer>` and
 :ref:`serializer.encoder <reference-dic-tags-serializer-encoder>`. It's also