Deprecation of OCaml's ocaml-migrate-parsetree

Hello Debian OCaml maintainers,

I'm one of the maintainers of OCaml's `ocaml-migrate-parsetree` package and OCaml's `ppxlib` package.

As a heads-up: We've deprecated `ocaml-migrate-parsetree`, as it has been superseded by `ppxlib`.

`ocaml-migrate-parsetree` is still being packaged as a Debian package. The problem with that is that `ocaml-migrate-parsetree` will be incompatible with new OCaml versions. So to update the Debian OCaml version to 5.1.0 or higher, you'll need to give up on the Debian `ocaml-migrate-parsetree` package, which wouldn't cause any problem as far as I can tell.

If you have any questions, please let me know.

Btw, you can also read more about the deprecation on an OCaml discuss post I've written: https://discuss.ocaml.org/t/rfc-deprecating-ocaml-migrate-parsetree-in-favor-of-ppxlib-also-as-a-platform-tool/13240

Kind regards,

Sonja