Changes golang build cache location
Changes golang build cache location

When using the golang Docker image as non-root, you don't have permissions to
create `/.cache/go-build` within the container. Presumably golang should check
have a more sane default build cache in such a situation. It sounds as though
this is indeed the behavior that has been pulled into upstream. However, it is
not clear why the behavior isn't fixed with current golang Docker image.
[Upstream bug](https://github.com/docker-library/golang/issues/225)

stuphlabs/pullcord,stuphlabs/pullcord