make Rivet_i compatible with Rivet/YODA 3.1.2/1.8.3

This change set syncs Rivet_i back with 21.6 and fix all the compiler issues previously seen. With this MR it should be fine to include it back into the Nightly builds.

FYI @zmarshal @ewelina @jchapman @lcorpe @dkar

added master label

This merge request affects 1 package:

• Generators/Rivet_i

added Generators review-pending-level-1 labels

CI Result SUCCESS (hash 06d01e21)

	Athena	AthSimulation	AthGeneration	AnalysisBase
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 21458]

Changes look fine to me, but passing to L2 to approve, since I'm not familiar with the previous issues mentioned in the MR description.

added review-pending-level-2 label and removed review-pending-level-1 label

Looks fine to me as well, so approving.

Pavol [as L2 MR shifter]

added review-approved label and removed review-pending-level-2 label

merged

mentioned in commit 5dda44af

added sweep:ignore label