Merge branch '6.3' into 6.4

* 6.3:
  [configuration]: remove php<8 section, remove flex reference

Author: OskarStark

configuration.rst

@@ -927,17 +927,6 @@ To improve performance, you can optionally run the ``dump-env`` Composer command
     1.2 or later). The command is not registered by default, so you must register
     first in your services:
 
-    .. code-block:: yaml
-
-        # config/services.yaml
-        services:
-            Symfony\Component\Dotenv\Command\DotenvDumpCommand:
-                - '%kernel.project_dir%/.env'
-                - '%kernel.environment%'
-
-    In PHP >= 8, you can remove the two arguments when autoconfiguration is enabled
-    (which is the default):
-
     .. code-block:: yaml
 
         # config/services.yaml