Provide docker image

[cbix]

I'm looking forward to integrating @workos/emulate into a docker compose environment, it seems like the right thing to use for local dev and CI!

Currently however, there's no Dockerfile and official image.

[gjtorikian]

This is technically published to ghcr, but I need IT to flip it to public, so I'll leave this open until that's done (🔜 ).

[gjtorikian]

Done: https://github.com/workos/emulate/pkgs/container/emulate

Will work on tagging by version number next (eg both the version number and latest should be on the newest image; when 0.7 comes out, it becomes latest) in the workflow.