Fix API deprecation 2021-02-24

[simonfagerholm]

Solves breaking changes in https://api.slack.com/changelog/2020-11-no-more-tokens-in-querystrings-for-newly-created-apps=0

• Change way of sending token Authentication does not work with new Apps #114
• Use conversations instead of groups and channels Conversations API deprecation - Get-SlackGroup #113

[simonfagerholm]

@RamblingCookieMonster It would be great for someone else to test this with an older app (to confirm the docs are correct) and then push it through to a release to get the module working again

[simonfagerholm]

Also went ahead and updated the functions that rely on the deprecated groups and channels APIs

[RamblingCookieMonster]

yaks! #116 probably needs some fixing before this. Have you poked around the function changes and do they work as expected? I'll try to find time to do this but it might be a week or two, sorry!

[simonfagerholm]

Hi @RamblingCookieMonster!
I have tested some changed functionality related to channels and the token, but as I don't have a "before" state to compare against I can't confidently say it works exactly as before. The channels change I think is fine, but the groups I don't even know what to expect.

TLDR; They work technically, but might not give the same result as before regarding the groups endpoint.

[mhudson]

LGTM

[KeesCBakker]

Any progress on this?

[jeffrey-github12]

@RamblingCookieMonster sorry for bothering you, but if it's not too much trouble and you're ok with it, would you mind reviewing and merging this pull request (as well as considering looking over some of the other remaining open pull requests in this repo if you have time)?

I've used this PowerShell module in the past and really appreciate the time and effort that you put into it! Unfortunately it appears that Slack has deprecated some of the authentication APIs linked in your README prerequisites section, specifically the Grab a test token and Register a Slack app, grab a token , so I think this pull request is needed for authentication to work at this point.

Thanks again for creating this module and adding a lot of useful functions, I really appreciate it and I'm guessing many others do as well!

P.S.: If you have time, I am also curious if .NET Core / cross-platform functionality (e.g. PowerShell 7) support was added, I see in the README Notes section that the last status was "currently evaluating" and I did see some commits referencing .NET Core for some functions, I was just curious if you remember whether or not that was completed. Either way thanks again!