Adds link to the Knative CNCF Slack Channel (#6711)

Signed-off-by: Vishal Choudhary <sendtovishalchoudhary@gmail.com>

Fixes #

<!-- Please include the 'why' behind your changes if no issue exists -->

## Proposed Changes

<!-- Please categorize your changes:
- 🎁 Add new feature
- 🐛 Fix bug
- 🧹 Update or clean up current behavior
- 🗑️ Remove feature or internal logic
-->

- 🐛 Fix bug
- This link now takes you to the CNCF Knative Slack channel.

### Pre-review Checklist

<!-- If these boxes are not checked, you will be asked to complete these
requirements or explain why they do not apply to your PR. -->

- [ ] **At least 80% unit test coverage**
- [ ] **E2E tests** for any new behavior
- [x] **Docs PR** for any user-facing impact
- [ ] **Spec PR** for any new API feature
- [ ] **Conformance test** for any change to the spec

**Release Note**

<!--
📄 If this change has user-visible impact, write a release
note in the block
below. Include the string "action required" if additional action is
required of
users switching to the new release, for example in case of a breaking
change.

Write as if you are speaking to users, not other Knative contributors.
If this
change has no user-visible impact, no release note is needed.
-->

```release-note

```


**Docs**

<!--
📖 If this change has user-visible impact, link to an issue or PR in
https://github.com/knative/docs.
-->

Signed-off-by: Vishal Choudhary <sendtovishalchoudhary@gmail.com>

README.md

@@ -6,7 +6,7 @@
 [![LICENSE](https://img.shields.io/github/license/knative/eventing.svg)](https://github.com/knative/eventing/blob/main/LICENSE)
 [![codecov](https://codecov.io/gh/knative/eventing/branch/main/graph/badge.svg)](https://codecov.io/gh/knative/eventing)
 [![TestGrid](https://img.shields.io/badge/testgrid-eventing-informational?logo=data:image/x-icon;base64,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)](https://testgrid.knative.dev/eventing)
-[![Slack](https://img.shields.io/badge/Signup-Knative_Slack-white.svg?logo=slack)](https://slack.knative.dev)
+[![Slack](https://img.shields.io/badge/Signup-Knative_Slack-white.svg?logo=slack)](https://slack.cncf.io/)
 [![Slack](https://img.shields.io/badge/%23eventing-white.svg?logo=slack&color=522a5e)](https://knative.slack.com/archives/C9JP909F0)
 [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/5913/badge)](https://bestpractices.coreinfrastructure.org/projects/5913)