post_processing example crashes when trying to run

[louiidev]

Bevy version

tested on: 1da726e

I ran the example and it immediately crashes.

Additional information

example: examples/shader/post_processing.rs

compiler output:

thread 'main' panicked at 'Requested resource bevy_render::renderer::render_device::RenderDevice does not exist in the `World`. 
                Did you forget to add it using `app.insert_resource` / `app.init_resource`? 
                Resources are also implicitly added via `app.add_event`,
                and can be added by plugins.', examples/shader/post_processing.rs:243:35

[mockersf]

Should be fixed by #8553