Run publications workflow weekly instead of monthly

Now that duplicate prevention is in place, weekly runs are safe
and will pick up new papers faster.

Co-Authored-By: sbfnk-bot <sbfnk-bot@users.noreply.github.com>

Author: sbfnk

.github/workflows/update-publications.yaml

@@ -1,7 +1,7 @@
 on:
   workflow_dispatch:
   schedule:
-    - cron:  '0 5 1 * *'
+    - cron:  '0 5 * * 1'  # Every Monday at 5am UTC
 
 name: Update publications