Update project to work with wgpu 0.19#105

<!-- Thank you for making a pull request! Below are the recommended steps to validate that your PR will pass CI --> ## Checklist - [x] `cargo clippy` reports no issues - [x] `cargo doc` reports no issues - [?] [`cargo deny`](https://github.com/EmbarkStudios/cargo-deny/) issues have been fixed or added to `deny.toml` - [x] human-readable change descriptions added to the changelog under the "Unreleased" heading. - [x] If the change does not affect the user (or is a process change), preface the change with "Internal:" - [x] Add credit to yourself for each change: `Added new functionality @githubname`. ## Description I've updated the project to work with wgpu-0.19. I don't expect this PR to be merged since it depends on git branches of imgui and imgui-winit-support, but I'm offering it here for anyone else who wants to use the latest wgpu.