ocaml-ci doesn't respect the `version` field in opam packages

[MisterDA]

We're transitioning from the ocurl name to curl, I've thus added the version: "transition" to the dune-project and the opam file of the ocurl package. The package curl now conflicts with ocurl if ocurl's version isn't "transition". The problem is that ocaml-ci always uses dev as a version for packages. It then cannot solve.

https://ocaml.ci.dev/github/ygrek/ocurl/commit/1e7ef328962a14b310993403a87afb78180c6069/variant/%28analysis%29

2025-04-04 07:15.12 [INFO] Solving for deps_for_opam_dune_lint.opam, ocurl.dev, curl_lwt.dev, curl.dev
…
- curl -> (problem)
Rejected candidates:
curl.dev: Requires ocurl not(<> transition)

I suggest that if there's a version set, ocaml-ci should use it. Or if it finds version, use version~~dev.