Update core_affinity requirement from 0.7 to 0.8

Updates the requirements on [core_affinity](https://github.com/Elzair/core_affinity_rs) to permit the latest version.
- [Release notes](https://github.com/Elzair/core_affinity_rs/releases)
- [Commits](Elzair/core_affinity_rs@0.7.0...0.8.0)

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

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

Author: dependabot[bot]

benches/netbench/Cargo.toml

@@ -11,7 +11,7 @@ description = "A Rust program to measure bandwidth or latency over a Rust TCP co
 [dependencies]
 bytes = "1.1"
 clap = "2.34"
-core_affinity = "0.7"
+core_affinity = "0.8"
 hdrhist = "0.5"
 
 [target.'cfg(target_os = "hermit")'.dependencies.hermit-sys]