Rivet_i: hepmc2 compatibility

Fix compilation with hepmc2.

This merge request affects 1 package:

• Generators/Rivet_i

This merge request affects 1 file:

• Generators/Rivet_i/src/Rivet_i.cxx

added Generators main review-pending-level-1 labels

CI Result SUCCESS (hash 7e9ea13f)

	Athena	AthGeneration
externals
cmake
make
tests

Full details available on this CI monitor view. Check the JIRA CI status board for known problems
Athena: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-EL9 4667]

MR looks good to me, approving.

Cheers, Yuriy (L1)

removed review-pending-level-1 label

added review-approved label

merged

mentioned in commit 4fb7843d