Bump cpufeatures from 0.2.12 to 0.2.15

Bumps [cpufeatures](https://github.com/RustCrypto/utils) from 0.2.12 to 0.2.15.
- [Commits](RustCrypto/utils@cpufeatures-v0.2.12...cpufeatures-v0.2.15)

---
updated-dependencies:
- dependency-name: cpufeatures
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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