fix: remove unused requirement pytz (#422)

* fix: remove unused requirement pytz

* 🦉 Updates from OwlBot

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

setup.py

@@ -34,7 +34,6 @@
     # https://github.com/googleapis/google-cloud-python/issues/10566
     "google-cloud-core >= 1.4.1, <3.0.0dev",
     "packaging >= 14.3",
-    "pytz",
     "proto-plus >= 1.10.0",
 ]
 extras = {}

tests/unit/v1/test_watch.py

@@ -566,9 +566,9 @@ def test_on_snapshot_unknown_listen_type(self):
         )
 
     def test_push_callback_called_no_changes(self):
-        import pytz
-
-        dummy_time = (datetime.datetime.fromtimestamp(1534858278, pytz.utc),)
+        dummy_time = (
+            datetime.datetime.fromtimestamp(1534858278, datetime.timezone.utc),
+        )
 
         inst = self._makeOne()
         inst.push(dummy_time, "token")