Change datetime.now() to dt_util.now() (#26582)

* Change datetime.now() to dt_util.now() in cases where the functionality should stay the same

These changes should not affect the functionality, rather cleanup our codebase.

In general we would like integrations to not to use datetime.now() unless there's a very good
reason for it, rather use our own dt_util.now() which makes the code aware of our current time
zone.

* Use datetime.utcnow() for season sensor to get offset-naive utc time

* Revert "Use datetime.utcnow() for season sensor to get offset-naive utc time"

This reverts commit 5f36463d9c7d52f8e11ffcec7e57dfbc7b21bdd1.

* BOM sensor last_updated should be UTC as well

* Run black

* Remove unused last_partition_update variable

homeassistant/components/bom/sensor.py

@@ -13,6 +13,7 @@ import requests
 import voluptuous as vol
 
 import homeassistant.helpers.config_validation as cv
+import homeassistant.util.dt as dt_util
 from homeassistant.components.sensor import PLATFORM_SCHEMA
 from homeassistant.const import (
     CONF_MONITORED_CONDITIONS,
@@ -240,7 +241,7 @@ class BOMCurrentData:
             # Never updated before, therefore an update should occur.
             return True
 
-        now = datetime.datetime.now()
+        now = dt_util.utcnow()
         update_due_at = self.last_updated + datetime.timedelta(minutes=35)
         return now > update_due_at
 
@@ -251,8 +252,8 @@ class BOMCurrentData:
             _LOGGER.debug(
                 "BOM was updated %s minutes ago, skipping update as"
                 " < 35 minutes, Now: %s, LastUpdate: %s",
-                (datetime.datetime.now() - self.last_updated),
-                datetime.datetime.now(),
+                (dt_util.utcnow() - self.last_updated),
+                dt_util.utcnow(),
                 self.last_updated,
             )
             return
@@ -263,8 +264,10 @@ class BOMCurrentData:
 
             # set lastupdate using self._data[0] as the first element in the
             # array is the latest date in the json
-            self.last_updated = datetime.datetime.strptime(
-                str(self._data[0]["local_date_time_full"]), "%Y%m%d%H%M%S"
+            self.last_updated = dt_util.as_utc(
+                datetime.datetime.strptime(
+                    str(self._data[0]["local_date_time_full"]), "%Y%m%d%H%M%S"
+                )
             )
             return