remove gevent from recommended dependencies for gunicorn due to its incompatibility with trio

    install_requires=requires,

    extras_require={

        'ldap_authentication': ['ldap3'],

        'gunicorn': ['gevent', 'gunicorn'],

        'gunicorn': ['gunicorn'],

        'gunicorn-extra': ['redis', 'Flask-Session==0.3.1'],

        'ci': test_requires,

        'dev': dev_requires,