tf-a-lts-cleanup: Set up to run twice a week

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I90f97f15b73f979bf0e1732d8753b3894bb44bf4
diff --git a/tf-a-lts-cleanup.yaml b/tf-a-lts-cleanup.yaml
index d663c7a..8e35cc8 100644
--- a/tf-a-lts-cleanup.yaml
+++ b/tf-a-lts-cleanup.yaml
@@ -12,7 +12,7 @@
     - authorization:
         !include: authorization.yaml.inc
     triggers:
-        - timed: 'H 3 * * *'
+        - timed: 'H 3 * * 0,3'
     wrappers:
         - credentials-binding:
           - ssh-user-private-key: