Fix for Ansible 8

"Conditional is marked as unsafe, and cannot be evaluated." was
raised on this line.

See [1].

[1] https://docs.ansible.com/ansible/latest/porting_guides/porting_guide_8.html#playbook

Change-Id: I7a22415894590802d14d4521c2ecca1f1dd6aa4c

playbooks/container-image-pre.yaml

@@ -2,7 +2,7 @@
   tasks:
     - name: Verify repository naming scheme
       when: |
-        not zj_image.repository | regex_search("^quay.io/{{ zuul.project.name }}\\b")
+        not zj_image.repository | regex_search("".join("^quay.io/", zuul.project.name, "\\b")
       loop: "{{ container_images }}"
       loop_control:
         loop_var: zj_image