build: filter by arch to prevent duplicated

Author: SergioRibera

flake.nix

@@ -113,7 +113,7 @@
         }) architectures)) // (pkgs.lib.listToAttrs (map ({arch, ...} @ args: {
           name = "image-${arch}";
           value = containerPkg args;
-        }) architectures));
+        }) (builtins.catAttrs "arch" architectures)));
 
         apps = {
           help = {