2.1.224

Update epubcheck-ruby requirement from 4.2.6.0 to 5.0.0.0 (#312)

Updates the requirements on [epubcheck-ruby](https://github.com/takahashim/epubcheck-ruby) to permit the latest version.
- [Release notes](https://github.com/takahashim/epubcheck-ruby/releases)
- [Commits](https://github.com/takahashim/epubcheck-ruby/compare/v4.2.6.0...v5.0.0.0)

---
updated-dependencies:
- dependency-name: epubcheck-ruby
  dependency-type: direct:production
...

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