remove Symfony 5 deprecations

Author: xabbuh

components/cache/adapters/pdo_adapter.rst

@@ -40,13 +40,6 @@ You can also create this table explicitly by calling the
 :method:`Symfony\\Component\\Cache\\Adapter\\PdoAdapter::createTable` method in
 your code.
 
-.. deprecated:: 5.4
-
-    Using :class:`Symfony\\Component\\Cache\\Adapter\\PdoAdapter` with a
-    :class:`Doctrine\\DBAL\\Connection` or a DBAL URL is deprecated since Symfony 5.4
-    and will be removed in Symfony 6.0.
-    Use :class:`Symfony\\Component\\Cache\\Adapter\\DoctrineDbalAdapter` instead.
-
 .. tip::
 
     When passed a `Data Source Name (DSN)`_ string (instead of a database connection