gitlab: preserve base rules for container template

When extending the container template to allow scheduled pipelines in
upstream context, we must ensure that all the existing rules defined
by .base_job_template are preserved.

Fortunately since the new rule for scheduled pipelines can come at
the head of all other rules, not in the middle, we can just the obscure
'!reference' syntax to pull in all the pre-existing rules as a single
block.

This fixes

 * stable branches using the wrong tag name in container images
 * pushes to forks unconditionally running container builds

Fixes: 8bec7b9874
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Tested-by: Michael Tokarev <mjt@tls.msk.ru>
Fixes: 8bec7b9874 ("gitlab: add a weekly container building job")
Message-ID: <20260119135528.2738108-1-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

.gitlab-ci.d/container-template.yml

@@ -23,6 +23,5 @@
     - docker logout
   rules:
     # because we want to enable this for scheduled runs we also have to replicate the normal rules
-    - if: '$CI_PIPELINE_SOURCE == "schedule"'
-    - if: '$CI_PROJECT_NAMESPACE == $QEMU_CI_UPSTREAM && $CI_COMMIT_BRANCH =~ /^staging/'
-    - if: '$QEMU_CI && $CI_PROJECT_NAMESPACE != $QEMU_CI_UPSTREAM'
+    - if: '$CI_PIPELINE_SOURCE == "schedule" && $CI_PROJECT_NAMESPACE == $QEMU_CI_UPSTREAM'
+    - !reference [.base_job_template, rules]