Bump rehype-slug from 5.1.0 to 6.0.0

Bumps rehype-slug from 5.1.0 to 6.0.0.

Release notes

Sourced from rehype-slug's releases.

6.0.0

Change

• 295ac26 Update @types/hast, unified, utilities, etc migrate: update too
• 12f76f8 Change to require Node.js 16 migrate: update too
• 6855bcc Change to use exports migrate: don’t use private APIs

Full Changelog: https://github.com/rehypejs/rehype-slug/compare/5.1.0...6.0.0

Commits

• f90fc8f 6.0.0
• 12f76f8 Change to require Node.js 16
• 6855bcc Change to use exports
• 87da225 Refactor to move implementation to lib/
• 963f30c Refactor docs
• 463cd39 Refactor code-style
• 22f1ee7 Refactor to use node:test
• 4597690 Add ignore-scripts to .npmrc
• 8b862e1 Refactor Actions
• 9c6f669 Refactor package.json
• Additional commits viewable in compare view