maintainers: update nyanbinary (#273991)

maintainers/maintainer-list.nix

···
     name = "Nathan Viets";
   };
   nyanbinary = {
-    email = "[e-mail]";
+    email = "[e-mail]";
+    matrix = "@niko:conduit.rs";
     github = "nyabinary";
     githubId = 97130632;
     name = "Niko";