message: add Zulip site information
diff: @@ -132,4 +132,4 @@ jobs:
  run: |
  ~/.local/bin/zulip-send --stream miri --subject "Cron Job Failure" \
  --message '@**RalfJ** @**oli** the Miri cron job build failed. Please investigate!' \
  - --user $ZULIP_BOT_EMAIL --api-key $ZULIP_API_TOKEN
  + --user $ZULIP_BOT_EMAIL --api-key $ZULIP_API_TOKEN --site https://rust-lang.zulipchat.com
  