Sync dune generated opam file

Signed-off-by: Nathan Rebours <[email protected]>

Author: NathanReb

mdx.opam

@@ -36,6 +36,7 @@ depends: [
   "odoc-parser" {>= "0.9.0"}
   "lwt" {with-test}
   "alcotest" {with-test}
+  "odoc" {with-doc}
 ]
 build: [
   ["dune" "subst"] {dev}