changed API endpoint from v2 to v3.

mdrsclient/commands/mkdir.py

@@ -3,7 +3,7 @@ from argparse import Namespace
 from typing import Any
 from unicodedata import normalize
 
-from mdrsclient.api import FolderApi
+from mdrsclient.api import FoldersApi
 from mdrsclient.commands.base import BaseCommand
 from mdrsclient.exceptions import IllegalArgumentException
 
@@ -31,5 +31,5 @@ class MkdirCommand(BaseCommand):
         parent_folder = cls._find_folder(connection, laboratory, r_dirname)
         if parent_folder.find_sub_folder(r_basename) is not None or parent_folder.find_file(r_basename) is not None:
             raise IllegalArgumentException(f"Cannot create folder `{r_path}`: File exists.")
-        folder_api = FolderApi(connection)
+        folder_api = FoldersApi(connection)
         folder_api.create(normalize("NFC", r_basename), parent_folder.id)