Run build_voltha_pod_release template every 30min

Change-Id: Ie95ead4ac192d6549c64a19c3c1d54b08b41b567
diff --git a/jjb/cord-test/nightly-build-pipeline.yaml b/jjb/cord-test/nightly-build-pipeline.yaml
index fda3ee1..d654905 100644
--- a/jjb/cord-test/nightly-build-pipeline.yaml
+++ b/jjb/cord-test/nightly-build-pipeline.yaml
@@ -880,7 +880,7 @@
     triggers:
        - timed: |
                  TZ=America/Los_Angeles
-                 H {time} * * *
+                 H/30 * * * *
 
 - job-template:
     name: 'build_{config-pod}_voltha_{release}_test'