update Slack invitation links

[martin-mfg]

Update all links to Slack, because the old invitation expired.

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[wing328]

that's what i got using private mode in browser.

what error message did you get?

[martin-mfg]

Slackbot warned me some days ago that the invitation link I created would expire soon. Clicking the "Renew Link" button didn't work. Yesterday evening the link indeed expired:

"Somebody tried joining openapi-generator via your invitation link, which is already expired."

"Oh no, something went wrong. Please try again."

And the "Renew Link" button still didn't work.

In your screenshot you opened the new invitation link, not the old expired one it seems?

[wing328]

i tried both (yours and the one in our project's readme)

[wing328]

And the "Renew Link" button still didn't work.

did you set it to never expire?

[martin-mfg]

did you set it to never expire?

Yes. Back some month ago when the link expired for the 1st time and the renew button did work.

I just tried in a private window with the old invitation link as well, and indeed it worked. No idea why I got an error message yesterday evening then that somebody could not join.

Thanks for checking! I guess I can close this PR then.