Hello,

Slack has released updates to its library and we can start using it for it. 

We especially like one change.

> slack_sdk has no required dependencies. This means aiohttp is no longer automatically resolved.

I've looked through the documentation and it doesn't look like a difficult task, but I think it's still worth testing.
More info: https://slack.dev/python-slack-sdk/v3-migration/index.html#from-slackclient-2-x

Best regards,
Kamil Breguła
setup.py
When installing providers from sources we install all namespace packages found below airflow,
        including airflow and provider packages, otherwise defaults from setup.cfg control this.
        The kwargs in setup() call override those that are specified in setup.cfg.
        """
        if os.getenv(INSTALL_PROVIDERS_FROM_SOURCES) == 'true':
            setup_kwargs['packages'] = find_namespace_packages(include=['airflow*'])
    include_provider_namespace_packages_when_installing_from_sources()
    if os.getenv(INSTALL_PROVIDERS_FROM_SOURCES) == 'true':
        print("Installing providers from sources. Skip adding providers as dependencies")
    else:
        add_all_provider_packages()
    write_version()
    setup(
        distclass=AirflowDistribution,
        version=version,
        extras_require=EXTRAS_REQUIREMENTS,
        download_url=('https://archive.apache.org/dist/airflow/' + version),
        cmdclass={
            'extra_clean': CleanCommand,
            'compile_assets': CompileAssets,
            'list_extras': ListExtras,
            'install': Install,
            'develop': Develop,
        },
        test_suite='setup.airflow_test_suite',
        **setup_kwargs,
    )
if __name__ == "__main__":
    do_setup()