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/test_childdevice.py

@@ -1,6 +1,5 @@
 import inspect
-import sys
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 
 import pytest
 from freezegun.api import FrozenDateTimeFactory
@@ -58,10 +57,6 @@ async def test_childdevice_update(dev, dummy_protocol, mocker):
 
 
 @strip_smart
-@pytest.mark.skipif(
-    sys.version_info < (3, 11),
-    reason="exceptiongroup requires python3.11+",
-)
 async def test_childdevice_properties(dev: SmartChildDevice):
     """Check that accessing childdevice properties do not raise exceptions."""
     assert len(dev.children) > 0
@@ -125,7 +120,7 @@ async def test_parent_property(dev: Device):
 
 
 @has_children_smart
-@pytest.mark.requires_dummy()
+@pytest.mark.requires_dummy
 async def test_child_time(dev: Device, freezer: FrozenDateTimeFactory):
     """Test a child device gets the time from it's parent module.
 
@@ -135,7 +130,7 @@ async def test_child_time(dev: Device, freezer: FrozenDateTimeFactory):
     if not dev.children:
         pytest.skip(f"Device {dev} fixture does not have any children")
 
-    fallback_time = datetime.now(timezone.utc).astimezone().replace(microsecond=0)
+    fallback_time = datetime.now(UTC).astimezone().replace(microsecond=0)
     assert dev.parent is None
     for child in dev.children:
         assert child.time != fallback_time