The fetch-zuul-cloner and use-cached-repos roles rely on an
unrelated repo appearing in required-projects. To allow us to
move this repo to the Zuul tenant, change that to
opendev/base-jobs, a repo which will appear in both the current
and future tenants.
Change-Id: I06703638b69d94531ad396224669980db9ababd4
2cece282cc