Downgrade apache-airflow for macos with Python 3.7 temporarily.
Downgrade apache-airflow for macos with Python 3.7 temporarily.

The airflow tests are failing with segmentation fault with 1.10.14. This failure happens only with macos 10.14.6(Mohave) + Python 3.7 + airflow 1.10.14 + TF nightly(as of 01/24/2021).

PiperOrigin-RevId: 353773365

tensorflow/tfx,tensorflow/tfx