flame_flutter3d and flame_flutter3d_audio go to 0.8.4, the audio package
asking for the bridge that has UpdatesAtRoot. flutter3d_game_shooter goes
to 0.8.1: its chase brain credits a hit through hurtFocus, which is
flutter3d_sim 0.8.1's, so it asks for that release.

flutter3d_sim 0.8.1 and flutter3d_net 0.8.1 keep what 0.8.0 code wrote
to: ActorSystem.focusBody can still be set, deprecated since step
overwrites it, and NetSession.droppedCorrections still writes through to
the shared session. Code built against 0.8.0 compiles against both.