fix flake

flake.nix

@@ -4,9 +4,9 @@
     { self }:
     {
       templates = {
-        default = {
-          path = ./templates/default;
-          description = "A default template for a devenv-flake";
+        simple = {
+          path = ./templates/simple;
+          description = "A simple template for a devenv-flake";
           welcomeText = ''
             # `.devenv` and `.direnv` should be added to `.gitignore`
             ```sh
@@ -26,6 +26,7 @@
             ```
           '';
         };
+        default = self.templates.simple;
       };
     };
 }