Bump zeroize from 1.7.0 to 1.8.1

Bumps [zeroize](https://github.com/RustCrypto/utils) from 1.7.0 to 1.8.1.
- [Commits](RustCrypto/utils@zeroize-v1.7.0...zeroize-v1.8.1)

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

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