updates

modules/capabilities/nix.nix

@@ -14,6 +14,10 @@ in
       settings = {
         trusted-users = [ "@wheel" ];
         use-xdg-base-directories = true;
+        extra-substituters = [ "https://devenv.cachix.org" ];
+        extra-trusted-public-keys = [
+          "devenv.cachix.org-1:w1cLUi8dv3hnoSPGAuibQv+f9TZLr6cv/Hm9XgU50cw="
+        ];
 
         experimental-features = [
           "nix-command"