eb-garamond: add bengsparks as maintainer

pkgs/by-name/eb/eb-garamond/package.nix

···
     homepage = "http://www.georgduffner.at/ebgaramond/";
     description = "Digitization of the Garamond shown on the Egenolff-Berner specimen";
     maintainers = with maintainers; [
+      bengsparks
       relrod
       rycee
     ];