wgpu 0.7.1

Rusty WebGPU API wrapper
Documentation
# Change Log

### v0.7.1 (2021-03-30)
- Fix the WASM build by pinning the `sync` dependency

## v0.7 (2021-01-31)
- See https://github.com/gfx-rs/wgpu/blob/v0.7/CHANGELOG.md#v07-2020-08-30
- Features:
	- (beta) WGSL support
	- better error messages
- API changes:
	- new `ShaderModuleDescriptor`
	- new `RenderEncoder`

### v0.6.2 (2020-11-24)
- don't panic in the staging belt if the channel is dropped