dependencies: bump htmlunit from 2.66.0 to 2.68.0 (#2409)

Bumps [htmlunit](https://github.com/HtmlUnit/htmlunit) from 2.66.0 to 2.68.0.
- [Release notes](https://github.com/HtmlUnit/htmlunit/releases)
- [Commits](https://github.com/HtmlUnit/htmlunit/compare/2.66.0...2.68.0)

---
updated-dependencies:
- dependency-name: net.sourceforge.htmlunit:htmlunit
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>