Update asciidoctor-epub3 requirement from 2.1.0 to 2.1.3 (#393)
Updates the requirements on [asciidoctor-epub3](https://github.com/asciidoctor/asciidoctor-epub3) to permit the latest version.
- [Release notes](https://github.com/asciidoctor/asciidoctor-epub3/releases)
- [Changelog](https://github.com/asciidoctor/asciidoctor-epub3/blob/main/CHANGELOG.adoc)
- [Commits](https://github.com/asciidoctor/asciidoctor-epub3/compare/v2.1.0...v2.1.3)
---
updated-dependencies:
- dependency-name: asciidoctor-epub3
dependency-type: direct:production
...
Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
