Make dune >= 1.7 incompatible with OCaml 4.12

[kit-ty-kate]

Should be fixed in the next major release most probably ocaml/dune#3585

I suggest to merge this PR at the same time as the next release with a fix so that users won't have to rebuild their whole switch for nothing. cc @rgrinberg are there any release planned soon?

[camelus]

Commit: 39b993f

Good to see you Madam.

☀️ All lint checks passed 39b993f

• These packages passed lint tests: dune.1.11.0, dune.1.11.1, dune.1.11.2, dune.1.11.3, dune.1.11.4, dune.2.0.0, dune.2.0.1, dune.2.1.1, dune.2.1.2, dune.2.1.3, dune.2.2.0, dune.2.3.0, dune.2.3.1, dune.2.4.0, dune.2.5.0, dune.2.5.1, dune.2.6.0, dune.2.6.1

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☀️ Installability check (+0)

[rgrinberg]

are there any release planned soon?

We could make a point release with that fix if you'd like

[kit-ty-kate]

We could make a point release with that fix if you'd like

If you can that'd be amazing. I'm sure @ejgallego and other dev testers would be very happy.

[avsm]

I don't think adding an upper bound will cause a package recompile -- that's only if the archive or build/install instructions change. It would be good to get this in to make opam-repository more consistent as soon as possible @kit-ty-kate, and merge the dune point release subsequently

[kit-ty-kate]

I don't think adding an upper bound will cause a package recompile

Sadly it does. I tested it with opam 2.0.7 before saying that