build(deps): update sdl2 requirement from 0.37 to 0.38

Updates the requirements on [sdl2](https://github.com/Rust-SDL2/rust-sdl2) to permit the latest version.
- [Changelog](https://github.com/Rust-SDL2/rust-sdl2/blob/master/changelog.md)
- [Commits](Rust-SDL2/rust-sdl2@0.37.0...0.38.0)

---
updated-dependencies:
- dependency-name: sdl2
  dependency-version: 0.38.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Cargo.toml

@@ -18,4 +18,4 @@ documentation = "https://docs.rs/vinylla/"
 
 [dev-dependencies]
 hound = "3.4"
-sdl2 = "0.37"
+sdl2 = "0.38"