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
]
statsd = [
    'statsd>=3.3.0, <4.0',
]
tableau = [
    'tableauserverclient~=0.12',
]
vertica = [
    'vertica-python>=0.5.1',
]
virtualenv = [
    'virtualenv',
]
webhdfs = [
    'hdfs[avro,dataframe,kerberos]>=2.0.4',
]
winrm = [
    'pywinrm~=0.4',
]
yandexcloud = [
    'yandexcloud>=0.22.0',
]
zendesk = [
    'zdesk',
]
all_dbs = (
    cassandra
    + cloudant
    + druid
    + exasol