maintainers: add ctucx

maintainers/maintainer-list.nix

···
     githubId = 202474;
     name = "Jens Reimann";
   };
+  ctucx = {
+    email = "[e-mail]";
+    github = "katjakwast";
+    githubId = 176372446;
+    name = "Katja Kwast";
+  };
   curran = {
     email = "[e-mail]";
     github = "curranosaurus";