CLI Testing via Docker Image

[HistoireDeBabar]

At the moment we have numerous unit tests to cover the lower level functionality of classes.

However, we don't have a good way to test a change that simulates how the action would be run in Github. It would be handy to have some end to end tests that build and run the Docker Image as a way to prevent breaking changes going out.

Perhaps a good start would be building the image and running the 'build' command for different runtimes. This is usually thing that fails most when rolling out changes or introducing new runtimes.