These internal `gcr.io/heptio-images/golang` images are deprecated. It looks like `git` and `bash` are the only things the Ark build needed that aren't in the upstream `golang:1.9-alpine3.6` image.
Signed-off-by: Matt Moyer <moyer@heptio.com>
Use a custom builder image to do all of Ark's builds. This image now
contains k8s.io/code-generator for code generation.
Enable docker in travis to use the builder image.
Signed-off-by: Andy Goldstein <andy.goldstein@gmail.com>
