Can't install async (optional) dependencies in 3.26.2

[drasmuss]

The Slack SDK version

slack_sdk==3.26.2

Python runtime version

Python 3.9.16

OS info

N/A

Steps to reproduce:

1. pip install slack_sdk[optional]==3.26.2

Expected result:

Installation with asyncio dependencies included, as described in https://github.com/slackapi/python-slack-sdk?tab=readme-ov-file#dns-performance.

Actual result:

WARNING: slack-sdk 3.26.2 does not provide the extra 'optional', asyncio dependencies aren't installed, and attempting to use that functionality results in an error.

Note: this change was introduced in 69638bf#diff-aa105879908fd2bb65240fade83175ff1ed8f7a989981cd1d5277ad842908afe. In that PR the optional requirements were moved to requirements/optional.txt, but that requires users to clone the repo and then manually install using that requirements file, which is pretty inconvenient.

[WilliamBergamin]

Hi @drasmuss thanks for writing in 💯

This is a great catch, I'll work on a fix and have it out soon