Fix import and update async timeout (#509)

src/p1monitor/p1monitor.py

@@ -5,21 +5,15 @@
 import socket
 from dataclasses import dataclass
 from importlib import metadata
-from typing import TYPE_CHECKING, Any, cast
+from typing import Any, Mapping, Self, cast
 
-import async_timeout
 from aiohttp import ClientError, ClientSession
 from aiohttp.hdrs import METH_GET
 from yarl import URL
 
 from .exceptions import P1MonitorConnectionError, P1MonitorError, P1MonitorNoDataError
 from .models import Phases, Settings, SmartMeter, WaterMeter
 
-if TYPE_CHECKING:
-    from collections.abc import Mapping
-
-    from typing_extensions import Self
-
 
 @dataclass
 class P1Monitor:
@@ -70,7 +64,7 @@ async def _request(
             self._close_session = True
 
         try:
-            async with async_timeout.timeout(self.request_timeout):
+            async with asyncio.timeout(self.request_timeout):
                 response = await self.session.request(
                     method,
                     url,