[libkwineffects] Bump api version

Summary:
libkwineffects in master is no longer ABI compatible with 0.227 because
order of virtual methods in EffectsHandler and EffectWindow had been
changed.

Reviewers: #kwin, davidedmundson

Reviewed By: #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D20652