ocamlPackages.irmin*: 2.1.0 → 2.2.0

source now inherit ppx_irmin instead of irmin, since we can test irmin
using ppx_irmin and this way we avoid circular dependencies.

pkgs/development/ocaml-modules/irmin/fs.nix

@@ -8,6 +8,8 @@ buildDunePackage rec {
 
   propagatedBuildInputs = [ irmin ];
 
+  useDune2 = true;
+
   checkInputs = lib.optional doCheck irmin-test;
 
   doCheck = true;