chore: add karpenter-dev channel for karpenter contributors

Author: ellistarn

communication/slack-config/channels.yaml

@@ -179,6 +179,7 @@ channels:
   - name: kalm
   - name: kaniko
   - name: karpenter
+  - name: karpenter-dev
   - name: k8s-dual-stack
     archived: true
   - name: k8s-infra-alerts