[AIRFLOW-XXXX] Less verbose docker builds
[AIRFLOW-XXXX] Less verbose docker builds

`-t` to xargs makes it echo the command it runs, we don't really need
that and it's overly verbose in our build logs

(cherry picked from commit 1a6b6cb0389582a288d9760bb6d02278c7fdff9f)

owlabs/incubator-airflow,owlabs/incubator-airflow,owlabs/incubator-airflow,owlabs/incubator-airflow