[AIRFLOW-5687] Fix Upgrade pip to 19.0.2 in CI build pipeline (#6361)
[AIRFLOW-5687] Fix Upgrade pip to 19.0.2 in CI build pipeline (#6361)

(cherry picked from commit 489e7fe9a77404cd8fe168627e5ddcb4b9152e25)

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