Speed up the Docker image creation in the `Trigger:qa-docker` job
In the gitlab-org/gitlab
project, the QA image building takes a bit more than 1 minute (e.g. https://gitlab.com/gitlab-org/gitlab/-/jobs/975458061) but in this project, the building take more than 8 minutes (e.g. https://gitlab.com/gitlab-org/build/omnibus-gitlab-mirror/-/jobs/975299810).
In gitlab-org/gitlab
we use Kaniko with the --cache
option.
An alternative and more radical solution would be to implement #5429 (closed).