[AIRFLOW-5239] Fix listing of pylint test scripts (#5844)
[AIRFLOW-5239] Fix listing of pylint test scripts (#5844)

List the two separate pylint scripts for use inside the Docker
containers in CONTRIBUTING.md.

(cherry picked from commit a47292d3d45002d0f972f81fe56b2d168af765e2)

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