Merge branch '6.0' into 6.1

* 6.0:
  [Serializer] Fix denormalizing union types
  [HttpFoundation] Remove obsolete override
  bug #42637 [Security] Fixed TOCTOU in RememberMe cache token verifier
  Fix compatibility of ldap 6.0 with security 5.x
  Add missing upgrade note for ldap
  [Mailer] Preserve case of headers

Author: nicolas-grekas

InputBag.php

@@ -40,14 +40,6 @@ public function get(string $key, mixed $default = null): string|int|float|bool|n
         return $this === $value ? $default : $value;
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function all(string $key = null): array
-    {
-        return parent::all($key);
-    }
-
     /**
      * Replaces the current input values by a new set.
      */