`dune-release opam pkg` should have `--skip-tests` to avoid generating `@runtest` alias

[anmonteiro]

some of my packages have testing setups that I don't want to run in the opam-repo for several reasons.

But there's no option in dune-release to avoid generating the @runtest alias in the opam repository.

[Leonidas-from-XIV]

At the moment you can remove the @runtest from the generated file before doing dune-release opam publish; that should achieve what you're meaning to do.