773: Panic on empty buffer slices r=kvark a=Wumpf
Fixes#735
Can't really pass through zero sizes, so panic it is.
I'm really just here to update to latest wgpu version to get my recent fix there in a more convenient manner, but doing a PR with just that felt a bit boring ;-). Now I'm of course guilty of conflating things 🤔
Co-authored-by: Andreas Reich <r_andreas2@web.de>