ocaml 5.4 is the default ocaml version

Author: EmileTrotignon

lib/Conf.ml

@@ -266,7 +266,7 @@ let default =
       ; disable= elt false
       ; margin_check= elt false
       ; max_iters= elt 10
-      ; ocaml_version= elt Ocaml_version.Releases.v4_04_0
+      ; ocaml_version= elt Ocaml_version.Releases.v5_4_0
       ; quiet= elt false
       ; disable_conf_attrs= elt false
       ; version_check= elt true } }