nixos/tests: add myself to maintainers of erofs test

nixos/tests/non-default-filesystems.nix

···
     makeTest {
       name = "non-default-filesystems-erofs";
 
+      meta.maintainers = with maintainers; [ nikstur ];
+
       nodes.machine = _: {
         virtualisation.qemu.drives = [{
           name = "non-default-filesystem";