Update all dependencies

[expenses]

I've tried to be pretty conservative here and not modernise the code that doesn't need to be. This unfortunately still doesn't fix #59 :^( . When I run it with env METAL_DEVICE_WRAPPER_TYPE=1 I do get a panic with:
validateFunctionArguments:3727: failed assertion 'Fragment Function(main0): argument v_69[0] from buffer(0) with offset(0) and length(176) has space for 176 bytes, but argument has a length(224).'

I'll see if switching to naga fixes this, and if not, I'll have a go at a gfx backend.

[repi]

As the renderer is so simple was a bit curious trying out wgpu crate on top of gfx later for a renderer instead of pure Metal. So if you want to take on some more work and experiment that that would be cool!

[expenses]

As the renderer is so simple was a bit curious trying out wgpu crate on top of gfx later for a renderer instead of pure Metal. So if you want to take on some more work and experiment that that would be cool!

That'd be ideal, but we've just added a pipeline cache for the gfx metal backend (gfx-rs/gfx#3719) and it might be a while until that's usable from wgpu. I'll see how things go!