Update jsonwebkey requirement from 0.3 to 0.4 in /spiffe

Updates the requirements on [jsonwebkey](https://github.com/nhynes/jwk-rs) to permit the latest version.
- [Commits](https://github.com/nhynes/jwk-rs/commits)

---
updated-dependencies:
- dependency-name: jsonwebkey
  dependency-version: 0.4.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

spiffe/Cargo.toml

@@ -44,7 +44,7 @@ hyper-util = { version = "0.1.8", default-features = false, optional = true }
 
 [dev-dependencies]
 # jsonwebkey 0.4 pulls jsonwebtoken >=10.2 (edition 2024, Rust 1.85+)
-jsonwebkey = { version = "0.3", features = ["generate", "jwt-convert"] }
+jsonwebkey = { version = "0.4", features = ["generate", "jwt-convert"] }
 tokio = { version = "1", features = ["macros"] }
 once_cell = "1"