When you install Aiflow with an extra, the required provider packages should be installed automatically.

For example:

`pip instal apache-airflow[google]` should install apache-airlfow-providers-google package.
setup.py
return f'.release:{version_}+{sha}'
    else:
        return 'no_git_version'
def write_version(filename: str = os.path.join(*[my_dir, "airflow", "git_version"])):
    """
    Write the Semver version + git hash to file, e.g. ".dev0+2f635dc265e78db6708f59f68e8009abb92c1e65".
    :param str filename: Destination file to write
    """
    text = "{}".format(git_version(version))
    with open(filename, 'w') as file:
        file.write(text)
amazon = [
    'boto3>=1.12.0,<2.0.0',
    'watchtower~=0.7.3',
]
apache_beam = [
    'apache-beam[gcp]',
]
async_packages = [
    'eventlet>= 0.9.7',
    'gevent>=0.13',
    'greenlet>=0.4.9',
]
atlas = [
    'atlasclient>=0.1.2',
]
azure = [
    'azure-batch>=8.0.0',
    'azure-cosmos>=3.0.1,<4',
    'azure-datalake-store>=0.0.45',