Wrap publishing steps into composite actions.

We follow a pattern in our package repos where we create a `CI_CD.yml` workflow that calls some reusable workflows from `shared`, but our publishing jobs in each `CI_CD.yml` are multistep jobs calling 3rd-party actions. These publishing jobs don't work properly when called from a reusable workflow, which prevents us from wrapping all the jobs in each consuming repo's `CI_CD.yml` into a single reusable workflow in `shared`. So, if we update how we do CI/CD, it often means we need to update all the `CI_CD.yml` files in each repo.

We may be able to use GitHub's composite actions to wrap up the publishing steps and the whole CI/CD pipeline into one reusable workflow. https://docs.github.com/en/actions/sharing-automations/avoiding-duplication