Improvements:
- `rules` directory can be also provided via `karton.ini` entry and `KARTON_YARAMATCHER_RULES` env var (https://github.com/CERT-Polska/karton-yaramatcher/pull/23)
Bugfixes:
- `KartonYaramatcher.main()` correctly instantiates Karton class when it is derived (e.g. to extend filters, also fixed in https://github.com/CERT-Polska/karton-yaramatcher/pull/23)