misc: replace uses of pytz.utc with timezone.utc where it makes sense

tests/takeout.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-from datetime import datetime
+from datetime import datetime, timezone
 from itertools import islice
 import pytz
 
@@ -43,7 +43,7 @@ def test_myactivity_search() -> None:
     results = list(read_html(tpath, path))
 
     res = (
-        datetime(year=2018, month=12, day=17, hour=8, minute=16, second=18, tzinfo=pytz.utc),
+        datetime(year=2018, month=12, day=17, hour=8, minute=16, second=18, tzinfo=timezone.utc),
         'https://en.wikipedia.org/wiki/Emmy_Noether&usg=AFQjCNGrSW-iDnVA2OTcLsG3I80H_a6y_Q',
         'Emmy Noether - Wikipedia',
     )

tests/tweets.py

@@ -3,11 +3,9 @@ from my.tests.common import skip_if_not_karlicoss as pytestmark
 # should make lazy loading the default..
 
 
-from datetime import datetime
+from datetime import datetime, timezone
 import json
 
-import pytz
-
 
 def test_tweet() -> None:
     from my.twitter.archive import Tweet
@@ -45,7 +43,7 @@ def test_tweet() -> None:
     """
     t = Tweet(json.loads(raw), screen_name='whatever')
     assert t.permalink is not None
-    assert t.dt == datetime(year=2012, month=8, day=30, hour=7, minute=12, second=48, tzinfo=pytz.utc)
+    assert t.dt == datetime(year=2012, month=8, day=30, hour=7, minute=12, second=48, tzinfo=timezone.utc)
     assert t.text == 'this is a test tweet'
     assert t.tid  == '2328934829084'
     assert t.entities is not None