fix: Update nixpkgs version for publish workflow, add comments on where to update nixpkgs

Author: AnarchoBooleanism

.github/workflows/publish.yaml

@@ -24,7 +24,7 @@ jobs:
       - name: "Install Nix"
         uses: cachix/install-nix-action@v31
         with:
-          nix_path: nixpkgs=channel:25.05
+          nix_path: nixpkgs=channel:25.11 # Change me on NixOS upgrades!
       - name: Build ISO images
         run: >
           nix run nixpkgs#nixos-generators -- \

flake.nix

@@ -2,7 +2,7 @@
   description = "Basic NixOS setup with cloud-init, intended to be made into an ISO";
 
   inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11"; # Change me on NixOS upgrades!
   };
 
   outputs = { self, nixpkgs }: {