Update rayon requirement from =1.5.1 to =1.8.0

Updates the requirements on [rayon](https://github.com/rayon-rs/rayon) to permit the latest version.
- [Changelog](https://github.com/rayon-rs/rayon/blob/master/RELEASES.md)
- [Commits](rayon-rs/rayon@v1.5.1...rayon-core-v1.6.1)

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

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

Cargo.toml

@@ -16,7 +16,7 @@ byteorder = "=1.4.0"
 cc = "=1.0.78"
 jobserver = "=0.1.25"
 log = "=0.4.17"
-rayon = "=1.5.1"
+rayon = "=1.8.0"
 rayon-core = "=1.10.0"
 regex = "=1.7.1"
 regex-syntax = "=0.6.28"