CLI updater #66
Description
In order to build updated versions of the docker images locally, they will need local versions. To ensure that they have them with the current structure, the easiest thing may be to have the CLI auto-update when invoked.
It can query the GitHub releases API to get the latest release (using google/go-github). If it is not the current version of the images, it could update itself by downloading the binary using the same API. It could prompt the user to rerun or restart itself using the os/exec package.