libkookie: update build-on-remote

infra/libkookie/build-on-remote

@@ -13,7 +13,7 @@ fi
 
 drvs="$(nix-instantiate -A system '<nixpkgs/nixos>' \
             -I nixos-config="$ROOT" \
-            -I "nixpkgs=$DIR/nixpkgs" \
+            -I "nixpkgs=$DIR/nixpkgs/unstable" \
             -I "nixpkgs-overlays=$DIR/overlays" \
             -I "home-manager=$DIR/home-manager" \
             -I "modules=$DIR/modules" \

infra/libkookie/default.nix

@@ -1,6 +1,6 @@
 { overlays ? [], ... } @ args:
 
-import ./nixpkgs (args // {
+import ./nixpkgs/unstable (args // {
   overlays = [ (import ./overlays) ] ++ overlays;
 })