Update .zuul.yaml

Author: SeanMooney

.zuul.yaml

@@ -177,20 +177,14 @@
 
 - project:
     name: openstack-k8s-operators/nova-operator
-    default-branch: main
+    default-branch: 18.0-fr1
     github-check:
       jobs:
         - openstack-meta-content-provider
         - nova-operator-kuttl
         - nova-operator-tempest-multinode
         - nova-operator-tempest-multinode-ceph
 
-- pragma:
-    implied-branch-matchers: True
-    implied-branches:
-      - main
-      - master
-
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 #                                                        #
 #               Project Template                         #