Bump to version 0.20.0.

Fix SDL3 license and metadata.

Bump to 0.18.0. Cargo update.

Update to Dear ImGui 1.92.2b. Bump to 0.17.1.

Bump to version 0.17.0.

Fix dependency errors

Update DearImGui to 1.92.1. Bump to 0.16.

This is the big scaling font version, many changes in
the public API.

Bump to version 0.15.0.

Bump easy-imgui-filechooser version to 0.2.4.

Bump to 0.13.0.

Cargo update to all latest deps.