refactor(nix): rename default.nix to package.nix

flake.nix

@@ -2,10 +2,12 @@
   description = "Simple tunneler in Go that exposes local ports to the internet";
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
 
-  outputs = {
+  outputs =
+    {
       self,
       nixpkgs,
-  }: let
+    }:
+    let
       systems = [
         "x86_64-linux"
         "aarch64-linux"
@@ -13,11 +15,13 @@
         "aarch64-darwin"
       ];
 
-    forAllSystems = function: nixpkgs.lib.genAttrs systems (system: function nixpkgs.legacyPackages.${system});
-  in {
+      forAllSystems =
+        function: nixpkgs.lib.genAttrs systems (system: function nixpkgs.legacyPackages.${system});
+    in
+    {
       packages = forAllSystems (pkgs: rec {
         default = trok;
-      trok = pkgs.callPackage ./default.nix {};
+        trok = pkgs.callPackage ./package.nix { };
       });
 
       nixosModules.default = ./module.nix;