<!-- This template is a great use for issues that are feature::additions or technical tasks for larger issues.--> ### Proposal CD can be triggered by new package/container, and can be run manually with select a package/container. ### Why now we use only on file `.gitlab-ci.yml` for CI and CD, it can only be triggered by code(must checkout code first). it's hard to use when: 1. deploy the latest version success, but it has bug, so want to deploy the old version. now we can run the pipeline with select the old git tag, but it will re-compile(maybe a long time), if the user want to skip re-compile, he need write many code to check the package exists or not.  2. two package registries for dev and prod, write and build code in the dev project, after testing, push package to the prod package registry, how to deploy it?  It might be a good idea to split `.gitlab-cd.yml` from `.gitlab-ci.yml` ### Competitors https://help.coding.net/docs/cd/pipe/triggers.html <!-- Label reminders Use the following resources to find the appropriate labels: - https://gitlab.com/gitlab-org/gitlab/-/labels - https://about.gitlab.com/handbook/product/categories/features/ -->