fixed type errors when pylance type checking mode is strict.

mdrsclient/models/file.py

@@ -1,3 +1,5 @@
+from typing import Any
+
 from pydantic.dataclasses import dataclass
 
 from mdrsclient.models.utils import iso8601_to_user_friendly
@@ -11,7 +13,7 @@ class File:
     size: int
     thumbnail: str | None
     description: str
-    metadata: dict
+    metadata: dict[str, Any]
     download_url: str
     created_at: str
     updated_at: str