Use fileId instead of path in the store (#174)

* Use fileId instead as path when storing the updates

* Updates file name in the store

* Run pre-commit

Author: hbcarlos

jupyter_collaboration/handlers.py

@@ -7,7 +7,6 @@
 import json
 import time
 import uuid
-from pathlib import Path
 from typing import Any
 
 from jupyter_server.auth import authorized
@@ -85,9 +84,7 @@ async def prepare(self):
                     )
 
                 file = self._file_loaders[file_id]
-                path = self._file_id_manager.get_path(file_id)
-                path = Path(path)
-                updates_file_path = str(path.parent / f".{file_type}:{path.name}.y")
+                updates_file_path = f".{file_type}:{file_id}.y"
                 ystore = self._ystore_class(path=updates_file_path, log=self.log)
                 self.room = DocumentRoom(
                     self._room_id,