Release opam-ci-check to opam repository

[punchagan]

Currently, we want to use the CLI in opam-repo-ci as a package included in this repo, to keep the development iteration loop fast enough. But, eventually we want to have the CLI tool available for people to install from opam. We can release to opam repo the tool is "good enough".

What's the criteria for good enough?

• revdeps listing and testing is also integrated into the CI
• the frequency of changes to the CLI is fairly low