update opam file

opam

@@ -1,13 +1,13 @@
 
 opam-version: "1.2"
 name: "haxe"
-version: "3.4.4"
+version: "3.4.7"
 maintainer: ["Haxe Foundation <[email protected]>" "Andy Li <[email protected]>"]
 author: "Haxe Foundation <[email protected]>"
 homepage: "https://haxe.org/"
 bug-reports: "https://github.com/HaxeFoundation/haxe/issues"
 license: ["GPL2+" "MIT"]
-dev-repo: "https://github.com/HaxeFoundation/haxe"
+dev-repo: "https://github.com/HaxeFoundation/haxe.git"
 build: [
   [ "env" "OCAMLPARAM=safe-string=0,_" make ]
 ]
@@ -23,5 +23,6 @@ remove: [
 depends: [
   "ocamlfind" {build}
   "camlp4"    {build}
+  "conf-neko"
 ]
 available: [ ocaml-version > "4.02" ]