Bevy 0.14 update status

[luca-della-vedova]

We currently are on 0.12, 0.14 was released recently and almost all crates are ready, so we can look into it when it won't disrupt existing PRs too much.

Among other things to look forward to, there are:

• Automatic flush point insertion (for more intuitive before / after behavior)
• Fair bit of performance improvements
• Gizmos and primitive shapes (could reduce our code size a fair bit if we went for them)
• Cleanup on the asset processing side since async trait functions were stabilized

Dependency state:

• bevy_egui, released, 0.28
• bevy_mod_raycast, released, 0.18
• bevy_mod_outline, released, 0.8
• bevy_mod_infinite_grid, released, 0.13.
• bevy_gltf_export, git dependency, created a bevy_0.14 branch.
• bevy_polyline, released, 0.10
• bevy_stl, PR pending https://github.com/nilclass/bevy_stl/pull/14, will be 0.14, worst case use fork.
• bevy_obj, released, 0.14.

[luca-della-vedova]

Big blocker encountered where Commands are no longer Send and Sync https://discord.com/channels/691052431525675048/691052431974465548/1259464518539411570.

This breaks migration for the Widget systems implementation between 0.13 and 0.14. Investigating upstream.

Edit: PR opened https://github.com/bevyengine/bevy/pull/14392