build(deps): bump rstest from 0.20.0 to 0.21.0

Bumps [rstest](https://github.com/la10736/rstest) from 0.20.0 to 0.21.0.
- [Release notes](https://github.com/la10736/rstest/releases)
- [Changelog](https://github.com/la10736/rstest/blob/master/CHANGELOG.md)
- [Commits](la10736/rstest@v0.20.0...v0.21.0)

---
updated-dependencies:
- dependency-name: rstest
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Cargo.lock

@@ -56,7 +56,7 @@ tikv-jemalloc-ctl = "0.5.4"
 
 [dev-dependencies]
 mockall = "0.12"
-rstest = "0.20"
+rstest = "0.21"
 tempfile = "3.10.1"
 tower = { version = "0.4", features = ["util"] }
 http-body-util = "0.1.1"