deploy: take deploy-rs from cache

lib/deploy.nix

@@ -49,11 +49,23 @@ in {
     lib.recursiveUpdate
     (lib.mapAttrs
       (
-        _: c: {
+        _: c: let
+          system = c.pkgs.stdenv.hostPlatform.system;
+          # Unmodified nixpkgs
+          pkgs = import inputs.nixpkgs { inherit system; };
+          # nixpkgs with deploy-rs overlay but force the nixpkgs package
+          deployPkgs = import inputs.nixpkgs {
+            inherit system;
+            overlays = [
+              inputs.deploy-rs.overlay # or deploy-rs.overlays.default
+              (self: super: { deploy-rs = { inherit (pkgs) deploy-rs; lib = super.deploy-rs.lib; }; })
+            ];
+          };
+        in {
           hostname = getFqdn c;
           profiles.system = {
             user = "root";
-            path = inputs.deploy-rs.lib.${c.pkgs.stdenv.hostPlatform.system}.activate.nixos c;
+            path = deployPkgs.deploy-rs.lib.activate.nixos c;
           };
         }
       )