build(deps): update rstest requirement from 0.19.0 to 0.20.0

Updates the requirements on [rstest](https://github.com/la10736/rstest) to permit the latest version.
- [Release notes](https://github.com/la10736/rstest/releases)
- [Changelog](https://github.com/la10736/rstest/blob/master/CHANGELOG.md)
- [Commits](la10736/rstest@v0.19.0...v0.20.0)

---
updated-dependencies:
- dependency-name: rstest
  dependency-type: direct:production
...

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

ciborium/Cargo.toml

@@ -27,7 +27,7 @@ serde = { version = "1.0.170", default-features = false, features = ["alloc", "d
 
 [dev-dependencies]
 serde_bytes = "0.11"
-rstest = "0.19.0"
+rstest = "0.20.0"
 rand = "0.8"
 hex = "0.4"