Modernize Python code to 3.10+ with pyupgrade (#254)

- Update type hints in tests/conftest.py to use modern syntax
- Convert Dict[str, Any] to dict[str, Any]
- Convert List[Dict[str, Any]] to list[dict[str, Any]]
- All code now uses Python 3.10+ compatible syntax

Author: vinitkumar

tests/conftest.py

@@ -22,7 +22,7 @@ def sample_json_string() -> str:
 
 
 @pytest.fixture
-def sample_json_dict() -> Dict[str, Any]:
+def sample_json_dict() -> dict[str, Any]:
     """Return a sample JSON dictionary for testing.
 
     Returns:
@@ -36,7 +36,7 @@ def sample_json_dict() -> Dict[str, Any]:
 
 
 @pytest.fixture
-def sample_json_list() -> List[Dict[str, Any]]:
+def sample_json_list() -> list[dict[str, Any]]:
     """Return a sample JSON list for testing.
 
     Returns: