Merge pull request ocaml#28118 from mseri/dune

dune 3.15.3 is not compatible with ocaml 5.4

Author: mseri

packages/dune/dune.3.15.3/opam

@@ -26,6 +26,7 @@ homepage: "https://github.com/ocaml/dune"
 doc: "https://dune.readthedocs.io/"
 bug-reports: "https://github.com/ocaml/dune/issues"
 conflicts: [
+  "ocaml" {< "5.4"}
   "merlin" {< "3.4.0"}
   "ocaml-lsp-server" {< "1.3.0"}
   "dune-configurator" {< "2.3.0"}