time.mktime is not the inverse of time.gmtime, calendar.timegm is

feedparser unhelpfully returns struct_time values in UTC and mktime
assumes they're local. Ugh.

cry/feed.py

@@ -1,5 +1,6 @@
 # I guess this is it.
 import asyncio
+import calendar
 import dataclasses
 import functools
 import hashlib
@@ -111,9 +112,10 @@ class Entry:
             published = entry.get("updated_parsed")
         if published is not None:
             assert isinstance(published, tuple)
+
             # NOTE: Take insert_time if it's smaller; publish time errors generate
             #       posts from the future.
-            posted_at = min(int(time.mktime(published) * 1000), insert_time)
+            posted_at = min(int(calendar.timegm(published) * 1000), insert_time)
         else:
             posted_at = int(insert_time)