Enable state-version in defaults

nixosModules/clanCore/defaults.nix

@@ -8,6 +8,10 @@
 {
   imports = lib.optional (_class == "nixos") (
     lib.mkIf config.clan.core.enableRecommendedDefaults {
+
+      # Enable automatic state-version generation.
+      clan.core.settings.state-version.enable = true;
+
       # Use systemd during boot as well except:
       # - systems with raids as this currently require manual configuration: https://github.com/NixOS/nixpkgs/issues/210210
       # - for containers we currently rely on the `stage-2` init script that sets up our /etc
@@ -37,6 +41,7 @@
   };
 
   config = lib.mkIf config.clan.core.enableRecommendedDefaults {
+
     # This disables the HTML manual and `nixos-help` command but leaves
     # `man configuration.nix`
     documentation.doc.enable = lib.mkDefault false;