Announce opam-ci-check internally, to invite early user feedback

[shonfeder]

Once the linting functionality is integrated into the CI pipeline and we feel that it is in good shape, we should announce it internally and invite feedback, but with the caveat that users should not expect high priority response to feature requests at this stage.

This will let us start to exercise the parallel use case, and seed a transition into our phase 2 work on this project.

[punchagan]

Yes, and while we gather feedback on this, we could work on the phase 1 work for the revdeps, probably.