Make OCaml 5.00 the minimum version for postgresql

Author: mmottl

packages/postgresql/postgresql.5.3.2/opam

@@ -14,7 +14,7 @@ doc: "https://mmottl.github.io/postgresql-ocaml/api"
 bug-reports: "https://github.com/mmottl/postgresql-ocaml/issues"
 depends: [
   "dune" {>= "2.7"}
-  "ocaml" {>= "4.12"}
+  "ocaml" {>= "5.00"}
   "dune-compiledb"
   "dune-configurator"
   "conf-postgresql" {build}