remove nixpkgs-unstable

the current version of woodpecker-server in stable now has the features this was original used for, not other usages of unstable are in tree left so removing it.

flake.nix

@@ -6,7 +6,6 @@
     # https://nixos.org/manual/nixos/stable/#sec-upgrading
     # https://github.com/NixOS/nixpkgs
     nixpkgs.url = "github:nixos/nixpkgs/nixos-24.05-small";
-    nixpkgs-unstable.url = "github:nixos/nixpkgs/nixos-unstable-small";
 
     # Add nixos-generators as an input.
     # See here: https://github.com/nix-community/nixos-generators#using-in-a-flake
@@ -23,10 +22,9 @@
     };
   };
 
-  outputs = { self, nixpkgs, nixpkgs-unstable, nixos-generators, sops-nix, ... }:
+  outputs = { self, nixpkgs, nixos-generators, sops-nix, ... }:
     let
       system = "x86_64-linux";
-      pkgs-unstable = nixpkgs-unstable.legacyPackages."x86_64-linux";
     in
     {
       overlays = {
@@ -204,9 +202,6 @@
             self.nixosModules.prometheus-exporter
             ./config/hosts/woodpecker
           ];
-          specialArgs = {
-            inherit pkgs-unstable;
-          };
         };
 
         status = nixpkgs.lib.nixosSystem {