Publish weekly

To better utilise caches during the working week, we decided
to publish only weekly (as opposed to daily).
This is due to DockerHub-imposed limits.

Change-Id: Ib4710dae09e991c0ad21c44a64b2617e0fd4fdc6

Author: yoctozepto

.zuul.d/centos.yaml

@@ -16,7 +16,7 @@
         - kolla-build-centos8-source
         - kolla-ansible-centos8-source
         - kolla-ansible-centos8-source-upgrade
-    periodic:
+    periodic-weekly:
       jobs:
         - kolla-publish-centos8-source
         - kolla-publish-centos8-binary

.zuul.d/debian.yaml

@@ -9,7 +9,7 @@
       jobs:
         - kolla-build-debian-source-aarch64
         - kolla-ansible-debian-source-aarch64
-    periodic:
+    periodic-weekly:
       jobs:
         - kolla-publish-debian-source
         - kolla-publish-debian-source-aarch64

.zuul.d/ubuntu.yaml

@@ -26,7 +26,7 @@
         - kolla-ansible-ubuntu-source-upgrade:
             vars:
               kolla_python_version: 3.8
-    periodic:
+    periodic-weekly:
       jobs:
         - kolla-publish-ubuntu-source
         - kolla-publish-ubuntu-binary