newsboat - unmark as broken

newsboat builds fine on master/19.09
thus this commit should also be backported

https://hydra.nixos.org/job/nixos/trunk-combined/nixpkgs.newsboat.x86_64-linux#tabs-status

pkgs/applications/networking/feedreaders/newsboat/default.nix

@@ -53,6 +53,5 @@ rustPlatform.buildRustPackage rec {
     maintainers = with maintainers; [ dotlambda nicknovitski ];
     license     = licenses.mit;
     platforms   = platforms.unix;
-    broken = true;
   };
 }