Bump zeroize from 1.5.6 to 1.5.7

Bumps [zeroize](https://github.com/RustCrypto/utils) from 1.5.6 to 1.5.7.
- [Release notes](https://github.com/RustCrypto/utils/releases)
- [Commits](RustCrypto/utils@zeroize-v1.5.6...zeroize-v1.5.7)

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

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