Updated to latest wgpu (0.18.0) (#3505)

Tested on M1 Mac:
* native
* webgl, firefox
* webgpu, chrome

all looking normal


Updated minor ahash version because 0.8.1 got yanked. Added some deny
exceptions for now - we'll have to update winit soon to resolve glow
related cargo deny errors (not a big issue though since we don't expect
wgpu and glow backends to be used at the same time)

crates/eframe/src/web/web_painter_wgpu.rs

@@ -77,7 +77,7 @@ impl WebPainterWgpu {
 
         let instance = wgpu::Instance::new(wgpu::InstanceDescriptor {
             backends: options.wgpu_options.supported_backends,
-            dx12_shader_compiler: Default::default(),
+            ..Default::default()
         });
 
         let canvas = super::canvas_element_or_die(canvas_id);
@@ -237,7 +237,7 @@ impl WebPainter for WebPainterWgpu {
                                 b: clear_color[2] as f64,
                                 a: clear_color[3] as f64,
                             }),
-                            store: true,
+                            store: wgpu::StoreOp::Store,
                         },
                     })],
                     depth_stencil_attachment: self.depth_texture_view.as_ref().map(|view| {
@@ -245,12 +245,16 @@ impl WebPainter for WebPainterWgpu {
                             view,
                             depth_ops: Some(wgpu::Operations {
                                 load: wgpu::LoadOp::Clear(1.0),
-                                store: false,
+                                // It is very unlikely that the depth buffer is needed after egui finished rendering
+                                // so no need to store it. (this can improve performance on tiling GPUs like mobile chips or Apple Silicon)
+                                store: wgpu::StoreOp::Discard,
                             }),
                             stencil_ops: None,
                         }
                     }),
                     label: Some("egui_render"),
+                    occlusion_query_set: None,
+                    timestamp_writes: None,
                 });
 
                 renderer.render(&mut render_pass, clipped_primitives, &screen_descriptor);