Fix issue with python 3.9

Author: dgarros

infrahub_sdk/ctl/graphql.py

@@ -3,6 +3,7 @@
 import ast
 from collections import defaultdict
 from pathlib import Path
+from typing import Optional
 
 import typer
 from ariadne_codegen.client_generators.package import PackageGenerator, get_package_generator
@@ -112,7 +113,7 @@ async def export_schema(
 @app.command()
 @catch_exception(console=console)
 async def generate_return_types(
-    query: Path | None = typer.Argument(None, help="Location of the GraphQL query file(s)."),
+    query: Optional[Path] = typer.Argument(None, help="Location of the GraphQL query file(s)."),
     schema: Path = typer.Option("schema.graphql", help="Path to the GraphQL schema file."),
     _: str = CONFIG_PARAM,
 ) -> None: