Update opam file using the one in opam

result.opam

@@ -1,9 +1,17 @@
-opam-version: "1.2"
+opam-version: "2.0"
 maintainer: "opensource@janestreet.com"
 authors: ["Jane Street Group, LLC <opensource@janestreet.com>"]
 homepage: "https://github.com/janestreet/result"
-dev-repo: "https://github.com/janestreet/result.git"
+dev-repo: "git+https://github.com/janestreet/result.git"
 bug-reports: "https://github.com/janestreet/result/issues"
-license: "BSD3"
+license: "BSD-3-Clause"
 build: [["dune" "build" "-p" name "-j" jobs]]
-depends: ["dune" {build}]
+depends: [
+  "ocaml"
+  "dune" {>= "1.0"}
+]
+synopsis: "Compatibility Result module"
+description: """
+Projects that want to use the new result type defined in OCaml >= 4.03
+while staying compatible with older version of OCaml should use the
+Result module defined in this library."""