[Cache] Deprecate the DoctrineProvider class

Author: javiereguiluz

cache.rst

@@ -187,6 +187,11 @@ will create pools with service IDs that follow the pattern ``cache.[type]``.
             ;
         };
 
+.. deprecated:: 5.4
+
+    The ``default_doctrine_provider`` option is deprecated in Symfony 5.4 and
+    it will be removed in Symfony 6.0.
+
 .. _cache-create-pools:
 
 Creating Custom (Namespaced) Pools

components/cache/adapters/doctrine_adapter.rst

@@ -39,4 +39,9 @@ third parameters::
     A :class:`Symfony\\Component\\Cache\\DoctrineProvider` class is also provided by the
     component to use any PSR6-compatible implementations with Doctrine-compatible classes.
 
+    .. deprecated:: 5.4
+
+        The ``DoctrineProvider`` class is deprecated in Symfony 5.4 and it will
+        be removed in Symfony 6.0.
+
 .. _`Doctrine Cache`: https://github.com/doctrine/cache