Pick up latest powheg in 102 LHCB_7

This allows us to pick up the latest dynamic build of powheg-v2

Since the version is already in lcg_105_LHCB_7 it is already in the lhcb cvmfs area.

Although the gcc11 library does not exist the gcc12 library works, it has been tested in lhcb-sim10-gen.

@clemenci, @bcouturi : can one of you please check and merge? I need this for the Gauss Sim10 release