chore: use datetime.timezone.utc in device_registration and remove unused test constants

- Replace datetime.UTC with datetime.timezone.utc in DeviceRegistrationMixin.register_device
- Remove unused constants from test_heating_extended.py (_TARGET_TEMP, _MANUAL_MODE, _BOOST_MODE, _BOOST_MINS)

Author: KJonline

src/api/device_registration.py

@@ -116,7 +116,9 @@ async def process_device_challenge(self, challenge_parameters):
         timestamp = re.sub(
             r" 0(\d) ",
             r" \1 ",
-            datetime.datetime.now(datetime.UTC).strftime("%a %b %d %H:%M:%S UTC %Y"),
+            datetime.datetime.now(datetime.timezone.utc).strftime(
+                "%a %b %d %H:%M:%S UTC %Y"
+            ),
         )
         hkdf = await self.get_device_authentication_key(
             self.device_group_key,

tests/unit/test_heating_extended.py

@@ -10,10 +10,7 @@
 
 _TODAY = str(datetime.date(datetime.now()))
 _CURRENT_TEMP = 19.0
-_TARGET_TEMP = 21.0
-_MANUAL_MODE = "MANUAL"
 _SCHEDULE_MODE = "SCHEDULE"
-_BOOST_MODE = "BOOST"
 _BOOST_MINS = 5
 _OFF_MODE = "OFF"