Keeping the dockerfiles/Dockerfile.cross image at 1.13, as we don't
have more current versions of that image. However, I don't think it's
still used, so we should remove it.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
To help with this add a bad plugin which produces invalid metadata and arrange
for it to be built in the e2e container.
Signed-off-by: Ian Campbell <ijc@docker.com>
That is, the helper to be used from the plugin's `main`.
Also add a `helloworld` plugin example and build integration.
Signed-off-by: Ian Campbell <ijc@docker.com>
