Case C-309/18: Judgment of the Court (Ninth Chamber) of 2 May 2019 (reference for a preliminary ruling from the Tribunale Amministrativo Regionale per il Lazio — Italy) — Lavorgna Srl v Comune di Montelanico, Comune di Supino, Comune di Sgurgola, Comune di Trivigliano (Reference for a preliminary ruling — Public procurement — Directive 2014/24/EU — Labour costs — Automatic exclusion of a tenderer who has failed to state those costs separately in the tender — Principle of proportionality)