keyboard input for symbol characters doesn't work on linux

[wtholliday]

(May also not work on macOS)

To reproduce:

1. cargo run --example gallery
2. Attempt to enter a symbol character in the text editor (such as !@#$%^&*)

Possibly related to #43.

@ruza-net

[ruza-net]

I tried adding some missing match arms to src/event_loop.rs - e.g. VirtualKeyCode::Caret - but it didn't have any effect.

Maybe winit and wgpu need a version bump? That would require some fixing of incompatibilities on part of rui and vger. Might look into it when I have time.

[wtholliday]

@ruza-net I updated all the dependencies to the latest versions.