Update garde requirement from 0.20.0 to 0.21.0

Updates the requirements on [garde](https://github.com/jprochazk/garde) to permit the latest version.
- [Release notes](https://github.com/jprochazk/garde/releases)
- [Commits](jprochazk/garde@v0.20.0...v0.21.0)

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

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

examples/Cargo.toml

@@ -24,7 +24,7 @@ latest = ["k8s-openapi/latest"]
 [dev-dependencies]
 tokio-util.workspace = true
 assert-json-diff.workspace = true
-garde = { version = "0.20.0", default-features = false, features = ["derive"] }
+garde = { version = "0.21.0", default-features = false, features = ["derive"] }
 anyhow.workspace = true
 futures = { workspace = true, features = ["async-await"] }
 jsonpath-rust.workspace = true