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
airflow/providers/slack/hooks/slack.py
if token is not None:
            return token
        if slack_conn_id is not None:
            conn = self.get_connection(slack_conn_id)
            if not getattr(conn, 'password', None):
                raise AirflowException('Missing token(password) in Slack connection')
            return conn.password
        raise AirflowException('Cannot get token: No valid Slack token nor slack_conn_id supplied.')
    def call(self, api_method: str, *args, **kwargs) -> None:
        """
        Calls Slack WebClient `WebClient.api_call` with given arguments.
        :param api_method: The target Slack API method. e.g. 'chat.postMessage'. Required.
        :type api_method: str
        :param http_verb: HTTP Verb. Optional (defaults to 'POST')
        :type http_verb: str
        :param files: Files to multipart upload. e.g. {imageORfile: file_objectORfile_path}
        :type files: dict
        :param data: The body to attach to the request. If a dictionary is provided,
            form-encoding will take place. Optional.
        :type data: dict or aiohttp.FormData
        :param params: The URL parameters to append to the URL. Optional.
        :type params: dict
        :param json: JSON for the body to attach to the request. Optional.
        :type json: dict
        """
        self.client.api_call(api_method, *args, **kwargs)