maintainers: update email for cottand (#356569)

maintainers/maintainer-list.nix

···
     name = "Chris Ostrouchov";
   };
   cottand = {
-    email = "[e-mail]";
+    email = "[e-mail]";
     github = "cottand";
     githubId = 45274424;
     name = "Nico D'Cotta";