Remove support for python <3.11 (#1273)

Python 3.11 ships with latest Debian Bookworm. 
pypy is not that widely used with this library based on statistics. It could be added back when pypy supports python 3.11.

tests/smart/modules/test_autooff.py

@@ -2,7 +2,6 @@ from __future__ import annotations
 
 import sys
 from datetime import datetime
-from typing import Optional
 
 import pytest
 from pytest_mock import MockerFixture
@@ -23,7 +22,7 @@ autooff = parametrize(
     [
         ("auto_off_enabled", "enabled", bool),
         ("auto_off_minutes", "delay", int),
-        ("auto_off_at", "auto_off_at", Optional[datetime]),
+        ("auto_off_at", "auto_off_at", datetime | None),
     ],
 )
 @pytest.mark.skipif(

tests/smart/modules/test_firmware.py

@@ -74,7 +74,7 @@ async def test_update_available_without_cloud(dev: SmartDevice):
         pytest.param(False, pytest.raises(KasaException), id="not-available"),
     ],
 )
-@pytest.mark.requires_dummy()
+@pytest.mark.requires_dummy
 async def test_firmware_update(
     dev: SmartDevice,
     mocker: MockerFixture,

tests/smart/modules/test_waterleak.py

@@ -17,8 +17,7 @@ waterleak = parametrize(
     ("feature", "prop_name", "type"),
     [
         ("water_alert", "alert", int),
-        # Can be converted to 'datetime | None' after py3.9 support is dropped
-        ("water_alert_timestamp", "alert_timestamp", (datetime, type(None))),
+        ("water_alert_timestamp", "alert_timestamp", datetime | None),
         ("water_leak", "status", Enum),
     ],
 )