Update rstest requirement from 0.21.0 to 0.22.0

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@v0.21.0...v0.21.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Cargo.toml

@@ -43,7 +43,7 @@ bytes = "1.6.0"
 snafu = { version = "0.8.0", features = ["backtrace"] }
 lexical-core = "0.8.5"
 heapless = "0.8.0"
-rstest = "0.21.0"
+rstest = "0.22.0"
 pyo3 = { version = "0.21", features = ["multiple-pymethods"] }
 pyo3-log = "0.10"
 serde = "1"