build(deps-dev): bump typedoc-plugin-markdown from 3.15.3 to 3.15.4

Bumps [typedoc-plugin-markdown](https://github.com/tgreyuk/typedoc-plugin-markdown/tree/HEAD/packages/typedoc-plugin-markdown) from 3.15.3 to 3.15.4.
- [Release notes](https://github.com/tgreyuk/typedoc-plugin-markdown/releases)
- [Changelog](https://github.com/tgreyuk/typedoc-plugin-markdown/blob/master/packages/typedoc-plugin-markdown/CHANGELOG.md)
- [Commits](https://github.com/tgreyuk/typedoc-plugin-markdown/commits/typedoc-plugin-markdown@3.15.4/packages/typedoc-plugin-markdown)

---
updated-dependencies:
- dependency-name: typedoc-plugin-markdown
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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