Production limits may not be working with more recent Geant4 version

[lobis]

The current "officially" supported Geant4 version for REST is v10.4.3 however REST is also supported for the latest Geant4 version, v11.0.2 at the time of writing.

I have found that in this version of Geant4, some examples produce way many more tracks than in the reference Geant4 version v10.4.3. (can be checked for example in https://github.com/rest-for-physics/restG4/runs/6863322663?check_suite_focus=true)

This is probably due to the step limiters not working correctly for this version of Geant4 and we should update them. Some examples also take much more time to run, such as 08.Alphas possibly due to this.

[lobis]

This was addressed in #63, its due to an option of the physics list being turned on on the latests versions which was not turned on (or didn't exist) on the older versions of Geant4.