Switch to egui master to fix wgpu issues

There are some wgpu issues that are fixed in egui-master, so
let's switch to that.

This fixes notedeck so that it runs on both my intel graphics laptop
and amdgpu desktop.

Fixes: https://github.com/damus-io/notedeck/issues/28
Fixes: https://github.com/damus-io/notedeck/issues/42
Fixes: https://github.com/damus-io/notedeck/issues/141
Signed-off-by: William Casarin <jb55@jb55.com>

src/ui_preview/main.rs

@@ -42,7 +42,7 @@ impl PreviewRunner {
             Box::new(move |cc| {
                 let app = Into::<PreviewApp>::into(preview);
                 setup_cc(cc, is_mobile, light_mode);
-                Box::new(app)
+                Ok(Box::new(app))
             }),
         );
     }