Added release notes for v104r2p1

ReleaseNotes/v104r2p1.md

+2018-06-14 Geant4 v104r2p1
+===
+This release is based on `GEANT4 r10.4.2`, uses `LCG 93` and `Geant4Files v104r1`.
+
+This version is released on `Sim10` branch.
+
+## Latest Changes
+
+#### LHCb production G4 Physics List option1NoApplyCuts
+**[MR !39] Fixed a potential problem in option1NoApplyCuts physics list where protons and anti-protons cannot share processes/models of ionisation and multiple scattering**