gdrive: add workaround for #4507

Temporary workaround. Proper solution will be introduced in iterative/PyDrive2#48

Author: efiop

dvc/tree/gdrive.py

@@ -382,7 +382,7 @@ def _gdrive_download_file(
         gdrive_file = self._drive.CreateFile(param)
 
         gdrive_file.FetchMetadata(fields="fileSize")
-        size = gdrive_file["fileSize"]
+        size = int(gdrive_file["fileSize"])
 
         with Tqdm(
             desc=progress_desc,