aptly: Add missing gpg-key on repo publish update
requested to merge adalessandro/open-build-service:wip/adalessandro/aptly-missing-gpgkey into collabora/staging
Task https://phabricator.apertis.org/T8672
The gpg-key needs to be passed as an argument when a repository is re-published. This is now missing, so the wrong gpg-key is being used.