Update cta-build.yml

cta-build.yml

@@ -35,6 +35,7 @@ cta_rpm:
   image: centos:7
   script:
     - yum install -y yum-utils epel-release
+    - yum install centos-release-openstack-train
     - cp continuousintegration/docker/ctafrontend/cc7/etc/yum.repos.d/eos-citrine-depend.repo /etc/yum.repos.d/.
     - rpm -import https://storage-ci.web.cern.ch/storage-ci/storageci.key
     # CTA uses a fixed version of CEPH