Update to naga 0.12.0

[Dinnerbone]

wgpu 0.16.0 came out and with it, naga 0.12. Can you update naga_oil to use it please?

I had a go at updating naga_oil to it myself but I hit a bump when it came to gfx-rs/naga#2264 and I wasn't confident enough in knowing the code of this library to continue. Otherwise the changes weren't that difficult.

Thanks!

[robtfm]

i'll try and get to this soon. if you've got an otherwise-working fork you could try using a Composer::non_validating() - i'm not sure if that'll help but it's worth a shot.