maintainers: add viluon

maintainers/maintainer-list.nix

···
       fingerprint = "5814 50EB 6E17 E715 7C63  E7F1 9879 8C3C 4D68 8D6D";
     }];
   };
+  viluon = {
+    email = "[e-mail]";
+    github = "viluon";
+    githubId = 7235381;
+    name = "Ondřej Kvapil";
+  };
   vincentbernat = {
     email = "[e-mail]";
     github = "vincentbernat";