maintainers: add sarunint

maintainers/maintainer-list.nix

···
     githubId = 178904;
     name = "Daniel Ehlers";
   };
+  sarunint = {
+    email = "[e-mail]";
+    github = "sarunint";
+    githubId = 3850197;
+    name = "Sarun Intaralawan";
+  };
   sascha8a = {
     email = "[e-mail]";
     github = "sascha8a";