Try explicit chmod to fix Windows failure

Author: krassowski

python_packages/jupyter_lsp/jupyter_lsp/tests/test_virtual_documents_shadow.py

@@ -213,7 +213,8 @@ def run_shadow(message):
 @pytest.fixture
 def forbidden_shadow_path(tmpdir):
     path = Path(tmpdir) / "no_permission_dir"
-    path.mkdir(mode=0)
+    path.mkdir()
+    path.chmod(0o000)
 
     yield path