fix: optional union type errors

Author: mak626

graphene_pydantic/converters.py

@@ -97,6 +97,9 @@ def convert_pydantic_field(
     to the generated Graphene data model type.
     """
     declared_type = getattr(field, "annotation", None)
+    # Convert Python 11 UnionType to T.Union
+    if isinstance(declared_type, UnionType):
+        declared_type = T.Union[declared_type.__args__]
     field_kwargs.setdefault(
         "type" if GRAPHENE2 else "type_",
         convert_pydantic_type(