revert back to old ci

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

flake.nix

@@ -5,18 +5,32 @@
     nixpkgs.url = github:nixos/nixpkgs/nixos-unstable;
     utils.url = github:numtide/flake-utils;
     rust-overlay.url = github:oxalica/rust-overlay;
+    cargo2nix.url = github:cargo2nix/cargo2nix;
   };
 
-  outputs = { self, nixpkgs, utils, rust-overlay }:
+  outputs = { self, nixpkgs, utils, rust-overlay, cargo2nix }:
     utils.lib.eachDefaultSystem
       (system:
         let
-          overlays = [ (import rust-overlay) ];
+
+          overlays =
+            [
+              (import "${cargo2nix}/overlay")
+              rust-overlay.overlay
+            ];
+
           pkgs = import nixpkgs {
             inherit system overlays;
           };
+
+          rustPkgs = pkgs.rustBuilder.makePackageSet' {
+            rustChannel = "latest";
+            packageFun = import ./Cargo.nix;
+          };
+
         in
         rec {
+
           devShells = with pkgs; {
             default = mkShell
               {
@@ -47,16 +61,14 @@
                 ];
               };
           };
+
           devShell = devShells.default;
-          defaultPackage = pkgs.rustPlatform.buildRustPackage rec {
-            pname = "singh3";
-            version = "0.1.0";
-            src = ./.;
-            nativeBuildInputs = with pkgs; [
-              rust-bin.nightly.latest.default
-            ];
-            cargoSha256 = "sha256-04yTexSkFpa3KQKVvfi7NM1j4V7m08kHDqw98bxXT5M=";
+
+          packages = {
+            default = (rustPkgs.workspace.singh3 { }).bin;
           };
+
+          defaultPackage = packages.default;
         }
       );
 }