avoid hitting pull limits docker
change docker image for build stage to pull from registry.cern.ch/docker/library to avoid hitting the pull limit in docker, which prevents the image from being pulled when a user pushes too many commits. Details in https://gitlab.cern.ch/kubernetes/docs/-/blob/master/content/docs/Registry/quickstart.md?ref_type=heads
Edited by Minh Tuan Pham