Make tripleo jobs non-voting

Currently triple jobs are broken in master and zed because of[1].

However the recent announcement[2] implies master and zed of TripleO
will no longer be maintained and we are unsure whether the issue will
be fixed soon.

This makes the TripleO jobs non-voting to unblock gate quickly. We have
to decide whether we should drop these jobs once the decision is made
by the TripleO project and TC.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=2169466
[2] https://lists.openstack.org/pipermail/openstack-discuss/2023-February/032083.html

Related-Bug: #2007659
Change-Id: Id300f9a31b106b702ea0ebb890679a5fcc141e10

zuul.d/tripleo.yaml

@@ -4,6 +4,7 @@
 - job:
     name: tripleo-puppet-ci-centos-9-undercloud-containers
     parent: tripleo-ci-centos-9-undercloud-containers
+    voting: false
     irrelevant-files: &irrelevant_files
       - ^.*\.md$
       - ^.*\.rst$
@@ -25,6 +26,7 @@
 - job:
     name: tripleo-puppet-ci-centos-9-content-provider
     parent: tripleo-ci-centos-9-content-provider
+    voting: false
     irrelevant-files: *irrelevant_files
 
 - project-template:
@@ -50,6 +52,7 @@
 - job:
     name: tripleo-puppet-ci-centos-9-standalone
     parent: tripleo-ci-centos-9-standalone
+    voting: false
     irrelevant-files: *irrelevant_files
     vars:
       featureset_override: