Update syntex requirement from 0.42 to 0.58

Updates the requirements on [syntex](https://github.com/erickt/rust-syntex) to permit the latest version.
- [Release notes](https://github.com/erickt/rust-syntex/releases)
- [Commits](serde-deprecated/syntex@v0.42.0...v0.58.1)

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

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

Author: dependabot[bot]

Cargo.toml

@@ -8,7 +8,7 @@ build = "build.rs"
 [build-dependencies]
 bindgen = "0.37.0"
 glob = "0.2.11"
-syntex = "0.42" # keep syntex version in match with pnet_macros/Cargo.toml
+syntex = "0.58" # keep syntex version in match with pnet_macros/Cargo.toml
 pnet = "0.25.0"
 pnet_macros_support = "0.25.0"
 pnet_macros = "0.25.0"