Merge branch '6.1' into 6.2

* 6.1:
  [Security] Update custom_authenticator
  fix(serializer): missing empty_array_as_object in example

Author: javiereguiluz

security/custom_authenticator.rst

@@ -360,7 +360,7 @@ authenticator methods (e.g. ``createToken()``)::
     {
         // ...
 
-        public function authenticate(Request $request): PassportInterface
+        public function authenticate(Request $request): Passport
         {
             // ... process the request
 
@@ -372,7 +372,7 @@ authenticator methods (e.g. ``createToken()``)::
             return $passport;
         }
 
-        public function createToken(PassportInterface $passport, string $firewallName): TokenInterface
+        public function createToken(Passport $passport, string $firewallName): TokenInterface
         {
             // read the attribute value
             return new CustomOauthToken($passport->getUser(), $passport->getAttribute('scope'));

serializer.rst

@@ -101,7 +101,10 @@ resources. This context is passed to all normalizers. For example:
 * :class:`Symfony\\Component\\Serializer\\Normalizer\\DateTimeNormalizer` uses
   ``datetime_format`` key as date time format;
 * :class:`Symfony\\Component\\Serializer\\Normalizer\\AbstractObjectNormalizer`
-  uses ``empty_iterable_as_object`` to represent empty objects as ``{}`` instead
+  uses ``preserve_empty_objects`` to represent empty objects as ``{}`` instead
+  of ``[]`` in JSON.
+* :class:`Symfony\\Component\\Serializer\\Serializer`
+  uses ``empty_array_as_object`` to represent empty arrays as ``{}`` instead
   of ``[]`` in JSON.
 
 You can pass the context as follows::