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
'parameterized',
    'paramiko',
    'pipdeptree',
    'pre-commit',
    'pylint==2.5.3',
    'pysftp',
    'pytest',
    'pytest-cov',
    'pytest-instafail',
    'pytest-rerunfailures',
    'pytest-timeouts',
    'pytest-xdist',
    'pywinrm',
    'qds-sdk>=1.9.6',
    'requests_mock',
    'setuptools',
    'testfixtures',
    'wheel',
    'yamllint',
]
if PY3:
    devel += ['mypy==0.770']
else:
    devel += ['unittest2']
devel_minreq = cgroups + devel + doc + kubernetes + mysql + password
devel_hadoop = devel_minreq + hdfs + hive + kerberos + presto + webhdfs
PROVIDERS_REQUIREMENTS: Dict[str, Iterable[str]] = {
    "amazon": amazon,
    "apache.cassandra": cassandra,
    "apache.druid": druid,