log spam on vulkan when window is minimized

See https://github.com/aclysma/skulpin/issues/92

We should address the TODO:
```
//TODO: This can occur persistently when the app is minimized, so ignore
// if the size has not changed. However, we could also consider adding
// a counter to limit the frequency. (A sensible case for this is
// resizing a window - to avoid rebuilding swapchain every frame during
// the resize.
```