Ensure relaxed syntax for point-free actions is supported

Author: Lelio-Brun

packages/obelisk/obelisk.0.7.0/opam

@@ -14,7 +14,7 @@ depends: [
   "ocaml" {>= "4.08"}
   "dune" {>= "2.2.0"}
   "re"
-  "menhir" {>= "20181113"}
+  "menhir" {>= "20190613"}
 ]
 build: [
   ["dune" "subst"] {pinned}