[AIRFLOW-XXXX] Bump version to 1.10.9 & add Changelog
[AIRFLOW-XXXX] Add versions_added field to configs
[AIRFLOW-6312] Unpin marshmallow-sqlalchemy for Py>3.5 (apache#6861)
[AIRFLOW-XXX] Update Changelog
[AIRFLOW-XXX] Update version to 1.10.7
[AIRFLOW-XXX] Update date in changelog