wgpu upgraded to 0.15. demo working on linux (#2629)

crates/egui-wgpu/src/renderer.rs

@@ -554,6 +554,7 @@ impl Renderer {
                 dimension: wgpu::TextureDimension::D2,
                 format: wgpu::TextureFormat::Rgba8UnormSrgb, // Minspec for wgpu WebGL emulation is WebGL2, so this should always be supported.
                 usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
+                view_formats: &[wgpu::TextureFormat::Rgba8UnormSrgb],
             });
             let sampler = self
                 .samplers