Remove global variable with API auth backend (apache#9833)

[AIRFLOW-XXXX] Bump version to 1.10.9 & add Changelog

[AIRFLOW-XXXX] Bump version to 1.10.9 & add Changelog

[AIRFLOW-XXXX] Add versions_added field to configs

[AIRFLOW-XXXX] Add versions_added field to configs

[AIRFLOW-6312] Unpin marshmallow-sqlalchemy for Py>3.5 (apache#6861)

[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