chore(deps-dev): bump markdown-it-anchor from 8.6.3 to 8.6.4

Bumps [markdown-it-anchor](https://github.com/valeriangalliat/markdown-it-anchor) from 8.6.3 to 8.6.4.
- [Release notes](https://github.com/valeriangalliat/markdown-it-anchor/releases)
- [Changelog](https://github.com/valeriangalliat/markdown-it-anchor/blob/master/CHANGELOG.md)
- [Commits](valeriangalliat/markdown-it-anchor@v8.6.3...v8.6.4)

---
updated-dependencies:
- dependency-name: markdown-it-anchor
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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