Run the charm's jobs nightly (00h00m)

Change-Id: Ib8c2609db18a1ec0cb8788e5b91add6afded27d1
diff --git a/zuul.d/charm-cinder-storpool-iscsi.yaml b/zuul.d/charm-cinder-storpool-iscsi.yaml
index f6dfaf2..649e399 100644
--- a/zuul.d/charm-cinder-storpool-iscsi.yaml
+++ b/zuul.d/charm-cinder-storpool-iscsi.yaml
@@ -182,3 +182,15 @@
             branches: master
         - zaza-functional-jammy-yoga-edge:
             branches: master
+    periodic:
+      jobs:
+        - charm-tox-black:
+            branches: master
+        - charm-tox-pep8:
+            branches: master
+        - charm-tox-lint:
+            branches: master
+        - charm-tox-cover:
+            branches: master
+        - zaza-functional-focal-ussuri:
+            branches: master