release-notes: Favor slack over irc
In the past few months a lot of communication shifted from IRC to slack.
Time to adjust the rleease notes to guide users to slack.
@@ -87,7 +87,7 @@ $(functest)
Additional Resources
--------------------
- Mailing list: <https://groups.google.com/forum/#!forum/kubevirt-dev>
-- IRC: <irc://irc.freenode.net/#kubevirt>
+- Slack: <https://kubernetes.slack.com/messages/virtualization>
- An easy to use demo: <https://github.com/kubevirt/demo>
- [How to contribute][contributing]
- [License][license]
