docker: Changed default tag to be <repo-name>:build (previously was <repo-name>:<commit-hash>). This is to not clutter with redundant images, with the 'drawback' that build-images aren't properly 'versioned', but again they rarely change.
docker: Changed default tag to be <repo-name>:build (previously was <repo-name>:<commit-hash>). This is to not clutter with redundant images, with the 'drawback' that build-images aren't properly 'versioned', but again they rarely change.

helmesjo/hello-cd,helmesjo/hello-cd