add rook helm repo to lint job

Change-Id: If2da02f7da948e75cfaa30f4dca6b400fa35623e
diff --git a/jjb/lint.yaml b/jjb/lint.yaml
index 7db3452..9a672f5 100644
--- a/jjb/lint.yaml
+++ b/jjb/lint.yaml
@@ -128,6 +128,7 @@
       - shell: |
           helm init --client-only
           helm repo add incubator https://kubernetes-charts-incubator.storage.googleapis.com/
+          helm repo add rook-beta https://charts.rook.io/beta
           helm repo add cord https://charts.opencord.org/master
 
       - shell: !include-raw-escape: shell/helmlint.sh