Update rustracing requirement from 0.5.1 to 0.6.0

Updates the requirements on [rustracing](https://github.com/sile/rustracing) to permit the latest version.
- [Release notes](https://github.com/sile/rustracing/releases)
- [Commits](sile/rustracing@0.5.1...0.6.0)

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

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

pingora-cache/Cargo.toml

@@ -35,7 +35,7 @@ httpdate = "1.0.2"
 log = { workspace = true }
 async-trait = { workspace = true }
 parking_lot = "0.12"
-rustracing = "0.5.1"
+rustracing = "0.6.0"
 rustracing_jaeger = "0.7"
 rmp = "0.8"
 tokio = { workspace = true }