CODEOWNERS: add myself for lib/licenses.nix

There have been a couple of instances where I have by chance noticed PRs
which add non-free licenses without them being appropriately marked. I'd
like to be notified of proposed changes to licenses to make it less
likely that this sort of thing slips by.

.github/CODEOWNERS

@@ -107,8 +107,8 @@
 # Eclipse
 /pkgs/applications/editors/eclipse @rycee
 
-# https://github.com/NixOS/nixpkgs/issues/31401
-/lib/licenses.nix @ghost
+# Licenses
+/lib/licenses.nix @alyssais
 
 # Qt / KDE
 /pkgs/applications/kde @ttuegel