Provide the "latest" tag for gitlab-operator-catalog

While the operator gets published to catalogues maintained by Red Hat, it looks like there's a significant delay between a new tag being published here and when it appears in OperatorHub. This repo already provides the gitlab-operator-catalog image in its registry, but misses the latest tag, meaning that CatalogSource has to be updated manually every time a new version is released.

It would be great if you could provide a moving registry.gitlab.com/gitlab-org/cloud-native/gitlab-operator/bundle/gitlab-operator-catalog:latest image to cut the middleman. This is especially important when a new security release is out, but it cannot be easily applied as the operator only allows specific Helm chart versions defined in CHART_VERSIONS.