make main31Vincia.cxx compile for Py8.309
In Pythia8.309 the functionality of PowhegHooksVicia.h has been moved to PowhegHooks.h In this MR some changes are introduced to make main31Vincia.cxx compile for both Py8.309 and old versions
In Pythia8.309 the functionality of PowhegHooksVicia.h has been moved to PowhegHooks.h In this MR some changes are introduced to make main31Vincia.cxx compile for both Py8.309 and old versions