
**Apache Airflow version**:
1.10.13

**What happened**:
`force_logout_after` should be `force_log_out_after` in the code section https://github.com/apache/airflow/blob/master/airflow/settings.py#L372-L381. As `force_log_out_after` is actually used and written in https://github.com/apache/airflow/blob/c5700a56bb3b9a5b872bda0fe0d3de82b0128bdf/UPDATING.md#unify-user-session-lifetime-configuration.

**What you expected to happen**:
`force_logout_after` is renamed to `force_log_out_after`.
airflow/settings.py
"""Prepare SQLAlchemy engine args"""
    engine_args = {}
    pool_connections = conf.getboolean('core', 'SQL_ALCHEMY_POOL_ENABLED')
    if disable_connection_pool or not pool_connections:
        engine_args['poolclass'] = NullPool
        log.debug("settings.prepare_engine_args(): Using NullPool")
    elif 'sqlite' not in SQL_ALCHEMY_CONN:
        
        
        
        pool_size = conf.getint('core', 'SQL_ALCHEMY_POOL_SIZE', fallback=5)