Add x-maintenance-intent to your opam files

[hannesm]

Dear Madam or Sir,

due to the opam repository archival process, we are keen to have the maintainers of packages specify their intention. We noticed that merlin has a lot of releases, and are curious what your maintenance intention is.

You can read up on the policy at https://github.com/ocaml/opam-repository/blob/master/governance/policies/archiving.md and the x-maintenance-intent field at https://github.com/ocaml/opam-repository/blob/master/governance/policies/archiving.md#specification-of-the-x--fields-used-in-the-archiving-process

Thanks a lot for taking this into consideration. Please note that adding x-maintenance-intent in the latest release is sufficient (please feel free to PR such a field directly to the opam-repository).

Also note that if there exists a package that is to be retained in opam-repository, and this depends on a specific merlin version (not part of the maintenance-intent), this merlin version is kept -- so we don't end up in uninstallable packages.

[voodoos]

Hello @hannesm,

We maintain the latest releases of Merlin for the two last releases of the compiler and 4.14.
For example, the currently maintained versions are v4.18-414, v5.3-502 and v5.3-503.

I think that would translate into this value:
x-maintenance-intent: ["v(latest)-414" "v(latest)-(latest)" "v(latest)-(latest-1)"]

Does that feels right to you ? (I mean, is that the expected syntax ?)