message: only one Zulip cron job topic per month
diff: @@ -145,7 +145,7 @@ jobs:
  ZULIP_BOT_EMAIL: ${{ secrets.ZULIP_BOT_EMAIL }}
  ZULIP_API_TOKEN: ${{ secrets.ZULIP_API_TOKEN }}
  run: |
  - ~/.local/bin/zulip-send --stream miri --subject "Cron Job Failure $(date -uI)" \
  + ~/.local/bin/zulip-send --stream miri --subject "Cron Job Failure (miri, $(date -u +%Y-%m))" \
  --message 'Dear @**RalfJ** and @**oli**
  It would appear that the Miri cron job build failed. Would you mind investigating this issue?
  