Flag ocaml.5.4.0 with avoid-version (see ocaml/opam#6358)

[kit-ty-kate]

ocaml/opam#6358 would display more clearly which packages are tagged with avoid-version/deprecated. However in the case of ocaml where we would expect 5.4.0 to be shown in the same way to avoid confusion as to which version is the latest, it is more complicated due to the fact that detecting if such a package needs to be displayed differently would need a request from the solver for each version which seems too costly.

Thus i'm proposing to tag the ocaml packages that are still unreleased or in their pre-release phase with avoid-version and to untag them at the same time as the final release (in this case 5.4.0).

cc @Octachron does that seem ok to you? If so this step would be to be added to the release documentation.

Not to be merged before ocaml/opam#6358 has been discussed and merged.

[Octachron]

That seems very-reasonable to me, I imagine that we should also flags 5.3.1?

[kit-ty-kate]

I imagine that we should also flags 5.3.1?

I forgot about it but yes indeed