Increase kolf version

Summary: It had be stuck in 1.20 for more than 2 years/40 commits

Reviewers: #kde_games, yurchor, arojas, mlaurent, asturmlechner, twighk

Reviewed By: yurchor, mlaurent

Subscribers: kde-games-devel

Differential Revision: https://phabricator.kde.org/D26437