Merge pull request #7462 from enj/enj-patch-1

Add sig-auth-certificates-dev slack channel

Author: k8s-ci-robot

communication/slack-config/channels.yaml

@@ -420,6 +420,7 @@ channels:
   - name: sig-auth
   - name: sig-auth-authenticators-dev
   - name: sig-auth-authorizers-dev
+  - name: sig-auth-certificates-dev
   - name: sig-auth-kms-dev
   - name: sig-auth-triage
   - name: sig-autoscaling