[WIP] User group for Cluster API release team

[ykakarap]

This PR adds a slack user group for the Cluster API release team.

Which issue(s) this PR fixes:

Fixes #

[ykakarap]

/hold till all members are added.

[ykakarap]

/hold cancel

[sbueringer]

/lgtm

Didn't verify the IDs, but the slack IDs are fine based on our release team doc in CAPI.

[sbueringer]

/assign @jdumars (for approval) :)

[jdumars]

/approve

Yay team for organizing this effort!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jdumars, markyjackson-taulia, ykakarap

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• ~~communication/slack-config/OWNERS~~ [jdumars]

Approvers can indicate their approval by writing /approve in a comment Approvers can cancel approval by writing /approve cancel in a comment

[BenTheElder]

/retest

[BenTheElder]

/test pull-community-verify

[ykakarap]

/retest