git-unix 2.1.3: update opam file

Author: mseri

packages/git-unix/git-unix.2.1.3/opam

@@ -10,14 +10,14 @@ doc:          "https://mirage.github.io/ocaml-git/"
 synopsis:     "Virtual package to install and configure ocaml-git's Unix backend"
 
 build: [
-  ["dune" "subst"]
+  ["dune" "subst"] {dev}
   ["dune" "build" "-p" name "-j" jobs]
   ["dune" "runtest" "-p" name "-j1" "--no-buffer"] {with-test}
 ]
 
 depends: [
   "ocaml"             {>= "4.07.0"}
-  "dune"
+  "dune"              {>= "1.1"}
   "mmap"              {>= "1.1.0"}
   "cmdliner" {< "1.1.0"}
   "git-http"          {= version}