style: ruff format and the lint rules of the driver standard

Mechanical: ruff format, and ruff check --fix with the rule set every NAPALM
driver uses (E, F, I, UP, B at line length 100, Python 3.10). What ruff
cannot fix comes in the next commit.

tests/test_sdn.py

@@ -2,8 +2,7 @@
 
 from __future__ import annotations
 
-import pytest
-from tests.conftest import _build_mock_api, SDN_ZONES, SDN_VNETS
+from tests.conftest import _build_mock_api
 
 
 class TestGetVlans:
@@ -52,8 +51,8 @@ class TestGetVlans:
 
     def test_empty_sdn_returns_dict(self):
         from unittest.mock import patch
+
         from napalm_proxmox.driver import ProxmoxDriver
-        from tests.conftest import _build_mock_api
 
         mock_api = _build_mock_api(sdn_vnets=[], sdn_zones=[])
         drv = ProxmoxDriver("pve1", "root", "secret", optional_args={"verify_ssl": False})