The surface buffer stops storing a depth its format cannot hold, and a step
stops asking the machine what a sine is. flutter3d, flutter3d_shaders,
flutter3d_cpu, flutter3d_webgl and flutter3d_impeller carry the first;
flutter3d_sim and the three genres carry the second; flutter3d_backend and
flutter3d_testing carry the floors that keep an engine and a backend together.
The other thirteen packages are unchanged and stay at 0.5.0.