Add slack channels for krustlet

Signed-off-by: Karen Chu <[email protected]>

Description of Request:
Need a place to discuss Krustlet matters with the community.

Author: karenhchu

communication/slack-config/channels.yaml

@@ -152,6 +152,7 @@ channels:
   - name: krane
   - name: krew
   - name: krex
+  - name: krustlet  
   - name: kube-aws
   - name: kube-deploy
     archived: true