Remove utcnow

This removes the use of utcnow to avoid deprecation warnings, though
ideally this would be fixed instead by switching over to using aware
datetimes instead.

Author: pganssle

cachecontrol/caches/redis_cache.py

@@ -4,7 +4,7 @@
 
 from __future__ import division
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import TYPE_CHECKING, Optional, Union
 
 from cachecontrol.cache import BaseCache
@@ -26,7 +26,7 @@ def set(
         if not expires:
             self.conn.set(key, value)
         elif isinstance(expires, datetime):
-            delta = expires - datetime.utcnow()
+            delta = expires - datetime.now(timezone.utc).replace(tzinfo=None)
             self.conn.setex(key, int(delta.total_seconds()), value)
         else:
             self.conn.setex(key, expires, value)

cachecontrol/heuristics.py

@@ -4,7 +4,7 @@
 
 import calendar
 import time
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from email.utils import formatdate, parsedate, parsedate_tz
 from typing import TYPE_CHECKING, Any, Dict, Mapping, Optional
 
@@ -15,7 +15,7 @@
 
 
 def expire_after(delta: timedelta, date: Optional[datetime] = None) -> datetime:
-    date = date or datetime.utcnow()
+    date = date or datetime.now(timezone.utc).replace(tzinfo=None)
     return date + delta