skrooge: 2.12.0 -> 2.13.0

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/skrooge/versions.

These checks were done:

- built on NixOS
- ran ‘/nix/store/l83qij463yvk1nqxahdcm9amfnp7zdm8-skrooge-2.13.0/bin/skroogeconvert -h’ got 0 exit code
- ran ‘/nix/store/l83qij463yvk1nqxahdcm9amfnp7zdm8-skrooge-2.13.0/bin/skroogeconvert --help’ got 0 exit code
- found 2.13.0 with grep in /nix/store/l83qij463yvk1nqxahdcm9amfnp7zdm8-skrooge-2.13.0
- directory tree listing: https://gist.github.com/699ec87fffb73399c86ad11632ed9b17