Updates the base image for all arch releases to the new location (us.gcr.io/k8s-artifacts-prod/build-image) as well as to the latest version (v2.1.0). This should fix a number of vulnerabilities that are in the 1.0.0 base image release.
o Set -e to abort script if a command fails.
o Allow custom docker 'TAG' from the environment.
o Move arch suffix to version to allow all images to
be put into a single repository.
o Enable cross builds. When doing cross builds where the
host and target architectures are different 'RUN mkdir'
will fail since the target container cannot be run on
the host. To work around this, create the directories
in build-docker, then use ADD in the Dockerfile.
o Add Dockerfile-release.arm64
Signed-off-by: Geoff Levand <geoff@infradead.org>
