Update base.py

#245 #255 
* Try fix warning 'StrEnum'

custom_components/luxtronik/base.py

@@ -4,8 +4,8 @@
 
 from datetime import datetime
 from typing import Any
+from enum import StrEnum
 
-from homeassistant.backports.enum import StrEnum
 from homeassistant.components.sensor import RestoreSensor
 from homeassistant.components.water_heater import STATE_HEAT_PUMP
 from homeassistant.const import STATE_OFF, UnitOfTemperature, UnitOfTime