Example doesn't run successfully

I wasn't able to get the all_examples3 binary to run. It panics with this error on startup:

```console
$ cd examples3d
$ cargo run --bin all_examples3
wgpu error: Validation Error

Caused by:
In a RenderPass
note: encoder = ``
In a pass parameter
note: command buffer = ``
attachment's sample count 2 is invalid

thread 'main' panicked at 'Handling wgpu errors as fatal by default', [...]/wgpu-0.7.1/src/backend/direct.rs:1896:5
```

After doing a small amount of research it seems related to MSAA levels.