Case C-30/17: Judgment of the Court (Fourth Chamber) of 17 May 2018 (request for a preliminary ruling from the Naczelny Sąd Administracyjny — Poland) — Dyrektor Izby Celnej w Poznaniu v Kompania Piwowarska S.A. w Poznaniu (Reference for a preliminary ruling — Tax provisions — Excise duties — Directive 92/83/EEC — Article 3(1) — Alcohol and alcoholic beverages — Beer — Flavoured beer — Degree Plato — Method of calculation)