python3Packages.dashing: migrate to pyproject

As part of https://github.com/NixOS/nixpkgs/issues/515974

pkgs/development/python-modules/dashing/default.nix

@@ -2,20 +2,23 @@
   lib,
   buildPythonPackage,
   fetchPypi,
+  setuptools,
   blessed,
 }:
 
 buildPythonPackage rec {
   pname = "dashing";
   version = "0.1.0";
-  format = "setuptools";
+  pyproject = true;
 
   src = fetchPypi {
     inherit pname version;
     hash = "sha256-JRRgjg8pp3Xb0bERFWEhnOg9U8+kuqL+QQH6uE/Vbxs=";
   };
 
-  propagatedBuildInputs = [ blessed ];
+  build-system = [ setuptools ];
+
+  dependencies = [ blessed ];
 
   meta = {
     homepage = "https://github.com/FedericoCeratto/dashing";