Bump markdownz from 8.0.7 to 8.1.3 (#270)

Bumps [markdownz](https://github.com/zooniverse/markdownz) from 8.0.7 to 8.1.3.
- [Release notes](https://github.com/zooniverse/markdownz/releases)
- [Changelog](https://github.com/zooniverse/markdownz/blob/master/CHANGELOG.md)
- [Commits](zooniverse/markdownz@v8.0.7...v8.1.3)

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

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