docs: Update link to the new CNCF Slack channel

[terrytangyuan]

Signed-off-by: terrytangyuan terrytangyuan@gmail.com

Note on DCO:

If the DCO action in the integration test fails, one or more of your commits are not signed off. Please click on the Details link next to the DCO action for instructions on how to resolve this.

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• Optional. My organization is added to USERS.md.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).

[codecov]

Codecov Report

Merging #6044 (6af8528) into master (aa829c2) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6044   +/-   ##
=======================================
  Coverage   40.96%   40.96%           
=======================================
  Files         147      147           
  Lines       19682    19682           
=======================================
  Hits         8062     8062           
  Misses      10514    10514           
  Partials     1106     1106           

Impacted Files	Coverage Δ
util/settings/settings.go	41.46% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update aa829c2...6af8528. Read the comment docs.

[jannfis]

Is that actually the correct URL? If I click on that, I get a sign on page, but no possibility to create an account 🤔

[alexmt]

I think we've posted https://argoproj.github.io/community/join-slack in other places.

Can we update https://github.com/argoproj/argo-site/blob/master/static/community/join-slack.html instead and keep using https://argoproj.github.io/community/join-slack ?

[terrytangyuan]

@jannfis Good catch...It's the correct URL but looks like you do need an account in that workspace first before you can join the channels.

@alexmt Perhaps we can update that join-slack html to be a plain HTML instead of a redirect? The content would include instruction to join https://slack.cncf.io/ workspace and then provide links to different channels on that page. WDYT?

[terrytangyuan]

I discussed this with @alexmt who's going to reuse the existing link with instructions to join the CNCF workspace and channels. Closing this for now.