fix: update shuttle-axum requirement from 0.31.0 to 0.39.0

Updates the requirements on shuttle-axum to permit the latest version.

---
updated-dependencies:
- dependency-name: shuttle-axum
  dependency-type: direct:production
...

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

Cargo.toml

@@ -32,7 +32,7 @@ tower-http = { version = "0.4.4", features = ["tracing", "compression-br", "comp
 # Shuttle
 miette = { version = "5.10.0" }
 shuttle-runtime = { version = "0.31.0", features = ["next", "tracing-subscriber"] }
-shuttle-axum = { version = "0.31.0" }
+shuttle-axum = { version = "0.39.0" }
 shuttle-secrets = { version = "0.34.0" }
 tokio = { version = "1.33.0", features = ["full"] }
 axum = { version = "0.6.20" }