Add scope of work/support to README
@tmaczukin @steveazz Let's add a scope of work/support to the project README and documentation so that everyone is clear on what the fork is for.
Speaking to @tmaczukin previously, the intent of the fork was to publish the fixes we made to get docker-machine working for GitLab.com's Shared Runners and we're not planning on any active development or long-term maintenance of the project.
I think this is important to call out as our users and customers might get the wrong idea. See related issue (account management project, internal use only) for an example.