Update opam version

nix/default.nix

@@ -4,14 +4,12 @@
 let mk_buildInputs = { opamPackages ? [], nixPackages ? [] } :
     [ pkgs.gnugrep pkgs.gnused  pkgs.autoconf pkgs.gnumake pkgs.gcc pkgs.ncurses pkgs.time pkgs.python3 pkgs.perl pkgs.file] ++ nixPackages ++ opam2nix.build {
            specs = opam2nix.toSpecs ([ "ocamlfind" "zarith" "ocamlgraph" "yojson"
-                { name = "coq"; constraint = "=8.7.2";  }
-                { name = "why3" ; constraint = "=1.2.0"; }
-                { name = "why3-coq" ; constraint = "=1.2.0"; }
-                { name = "menhir"; constraint = "=20181113"; }
+                { name = "coq"; constraint = "=8.9.1";  }
+                { name = "why3" ; constraint = "=1.2.1"; }
+                { name = "why3-coq" ; constraint = "=1.2.1"; }
+                { name = "menhir"; constraint = "=20190924"; }
                 "camlzip" #so that why3 is always compiled with it
-                ] ++ opamPackages ++
-                (if ocaml_version == "pkgs.ocaml-ng.ocamlPackages_4_02.ocaml"
-                then [ { name = "ocamlbuild" ; constraint = "=0"; } ] else [])
+                ] ++ opamPackages
               );
            ocamlAttr = ocaml_version;
         };

nix/frama-ci.nix

@@ -5,8 +5,8 @@ let
     src = builtins.fetchGit {
             "url" = "https://bobot:${password}@git.frama-c.com/frama-c/Frama-CI.git";
             "name" = "Frama-CI";
-            "rev" = "cea0f2d2872e59fd3e6fe4634891a3765c7036e8";
-            "ref" = "feature/opam2";
+            "rev" = "a96860d3f174222af2c68bd53e2502f615f39bea";
+            "ref" = "feature/ci/update-opam";
     };
  in
  {