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
docs/conf.py
import airflow
from airflow.configuration import default_config_yaml
from docs.exts.docs_build.third_party_inventories import (  
    THIRD_PARTY_INDEXES,
)
sys.path.append(os.path.join(os.path.dirname(__file__), 'exts'))
CONF_DIR = os.path.abspath(os.path.join(os.path.dirname(__file__)))
INVENTORY_CACHE_DIR = os.path.join(CONF_DIR, '_inventory_cache')
ROOT_DIR = os.path.abspath(os.path.join(CONF_DIR, os.pardir))
FOR_PRODUCTION = os.environ.get('AIRFLOW_FOR_PRODUCTION', 'false') == 'true'
PACKAGE_NAME = os.environ.get('AIRFLOW_PACKAGE_NAME', 'apache-airflow')
PACKAGE_DIR: Optional[str]
if PACKAGE_NAME == 'apache-airflow':
    PACKAGE_DIR = os.path.join(ROOT_DIR, 'airflow')
    PACKAGE_VERSION = airflow.__version__
elif PACKAGE_NAME.startswith('apache-airflow-providers-'):
    from provider_yaml_utils import load_package_data  
    ALL_PROVIDER_YAMLS = load_package_data()
    try:
        CURRENT_PROVIDER = next(
            provider_yaml
            for provider_yaml in ALL_PROVIDER_YAMLS
            if provider_yaml['package-name'] == PACKAGE_NAME
        )
    except StopIteration:
        raise Exception(f"Could not find provider.yaml file for package: {PACKAGE_NAME}")
    PACKAGE_DIR = CURRENT_PROVIDER['package-dir']
    PACKAGE_VERSION = 'master'
else:
    PACKAGE_DIR = None