Support private Slack channels

[michal-jagiello-tmpl]

I configured Slack notifications for private channel but I get no messages. It works for public channels

Describe the solution you'd like Whatever which channel I select messages should be sent

Describe alternatives you've considered None -- working on public channels is an accepted workaround, but should work on private as well

[ypoplavs]

Hey @michal-jagiello-tmpl! Is this issue still relevant?

Please take a look at our documentation: https://docs.testkube.io/articles/slack-integration/ It should work with all channels.