Bumps [peaceiris/actions-mdbook](https://github.com/peaceiris/actions-mdbook) from 1 to 2.
- [Release notes](https://github.com/peaceiris/actions-mdbook/releases)
- [Changelog](https://github.com/peaceiris/actions-mdbook/blob/main/CHANGELOG.md)
- [Commits](peaceiris/actions-mdbook@v1...v2)

---
updated-dependencies:
- dependency-name: peaceiris/actions-mdbook
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

…mdbook-2