Bump clkhash from 0.17.0 to 0.18.1 (#569)

Bumps [clkhash](https://github.com/data61/clkhash) from 0.17.0 to 0.18.1.
- [Release notes](https://github.com/data61/clkhash/releases)
- [Changelog](https://github.com/data61/clkhash/blob/main/CHANGELOG.md)
- [Commits](data61/clkhash@v0.17.0...v0.18.1)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -1,5 +1,5 @@
 bitarray==2.6.0
-clkhash==0.17.0
+clkhash==0.18.1
 Cython==0.29.32
 hypothesis==6.9.2
 pytest>=7.0.1