Bump num_cpus from 1.14.0 to 1.15.0

Bumps [num_cpus](https://github.com/seanmonstar/num_cpus) from 1.14.0 to 1.15.0.
- [Release notes](https://github.com/seanmonstar/num_cpus/releases)
- [Changelog](https://github.com/seanmonstar/num_cpus/blob/master/CHANGELOG.md)
- [Commits](seanmonstar/num_cpus@v1.14.0...v1.15.0)

---
updated-dependencies:
- dependency-name: num_cpus
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Cargo.lock

@@ -157,7 +157,7 @@ rand = "0.8"
 
 futures = "0.3"
 tokio = { version = "1", features = ["rt", "signal"] }
-num_cpus = "1.13"
+num_cpus = "1.15"
 
 ipnet = { version = "2.7", optional = true }