Drop Support for EOL Python 3.6, 3.7 and 3.8

As of today per Python Software Foundation policy here: https://devguide.python.org/versions/

• Python 3.6 has ended security support and it's end of life was - 2021-12-23. It's 3 years unsupported!
• Python 3.7 has ended security support and it's end of life was - 2023-06-27. It's 1.5 years unsupported!
• Python 3.8 has ended security support and it's end of life was - 2024-10-07. It's 3 months unsupported!

Does Slack SDK plans to remove support for those Python versions? Promoting unsupported version of Python has security concerns and it shouldn't be promoted.

I've realised this while working on #1633 as I wasn't expecting that Python 3.6 is in use and I was using features that were added in Python 3.8 so I lived under assumption that I can use everything from 3.9 and above.

Category

• slack_sdk.web.WebClient (sync/async) (Web API client)
• slack_sdk.webhook.WebhookClient (sync/async) (Incoming Webhook, response_url sender)
• slack_sdk.models (UI component builders)
• slack_sdk.oauth (OAuth Flow Utilities)
• slack_sdk.socket_mode (Socket Mode client)
• slack_sdk.audit_logs (Audit Logs API client)
• slack_sdk.scim (SCIM API client)
• slack_sdk.rtm (RTM client)
• slack_sdk.signature (Request Signature Verifier)

Requirements

Please read the Contributing guidelines and Code of Conduct before creating this issue or pull request. By submitting, you are agreeing to those rules.

Aucun fichier, test ou point d’entrée n’est indiqué. Commencez par examiner la configuration du projet et les références CI aux versions de Python prises en charge, puis inspectez les composants du SDK listés pour vérifier leur prise en charge selon la version. Le travail est terminé lorsque Python 3.6, 3.7 et 3.8 ne sont plus pris en charge de manière cohérente dans ces composants et que la validation correspondante est mise à jour.