build(deps-dev): bump markdownlint-rule-relative-links

Bumps [markdownlint-rule-relative-links](https://github.com/theoludwig/markdownlint-rule-relative-links) from 5.1.0 to 5.1.2.
- [Release notes](https://github.com/theoludwig/markdownlint-rule-relative-links/releases)
- [Commits](https://github.com/theoludwig/markdownlint-rule-relative-links/compare/v5.1.0...v5.1.2)

---
updated-dependencies:
- dependency-name: markdownlint-rule-relative-links
  dependency-version: 5.1.2
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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