Update GenEvent.h -- fix HepMC2 compilation (!66095) · Merge requests · atlas / athena · GitLab

Andrii Verbytskyi requested to merge averbyts-main-patch-11762 into main Sep 27, 2023

Update GenEvent.h -- fix HepMC2 compilation in https://its.cern.ch/jira/browse/ATLASSIM-6895