added the missing support for pipelines

[Oreboat]

I have tested this in my own project, it does appear to work

[apotema]

Thanks for adding the pipeline bindings! I tested the PR and found an issue with the set_pipeline binding:

extern fn ecs_set_pipeline(world: *world_t, pipeline: entity_t, delta_time: ftime_t) void;

Should be

extern fn ecs_set_pipeline(world: *world_t, pipeline: entity_t) void;

https://github.com/SanderMertens/flecs/blob/master/include/flecs/addons/pipeline.h:
void ecs_set_pipeline(
ecs_world_t *world,
ecs_entity_t pipeline);

[Srekel]

Thanks! I must have missed this PR somehow. Please fix the function and I'll merge it :)