maintainers: add lactose

maintainers/maintainer-list.nix

···
     github = "lachrymaLF";
     githubId = 13716477;
   };
+  lactose = {
+    name = "lactose";
+    email = "[e-mail]";
+    github = "juuyokka";
+    githubId = 15185244;
+  };
   lafrenierejm = {
     email = "[e-mail]";
     github = "lafrenierejm";