build: bump num-traits from 0.2.14 to 0.2.15

Bumps [num-traits](https://github.com/rust-num/num-traits) from 0.2.14 to 0.2.15.
- [Release notes](https://github.com/rust-num/num-traits/releases)
- [Changelog](https://github.com/rust-num/num-traits/blob/master/RELEASES.md)
- [Commits](https://github.com/rust-num/num-traits/compare/num-traits-0.2.14...num-traits-0.2.15)

---
updated-dependencies:
- dependency-name: num-traits
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

Cargo.lock

@@ -575,9 +575,9 @@ dependencies = [
 
 [[package]]
 name = "num-traits"
-version = "0.2.14"
+version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
+checksum = "578ede34cf02f8924ab9447f50c28075b4d3e5b269972345e7e0372b38c6cdcd"
 dependencies = [
  "autocfg",
 ]