3.0.0

Change

• bf36a3f Update @types/hast, utilities
  migrate: update too
• 6477e39 Change to require Node.js 16
  migrate: update too
• 750a728 Change to use exports
  migrate: don’t use private APIs
• 66d8da6 Change to remove support for non-nodes
  migrate: pass valid input
• 9d15d29 Change to yield undefined
  migrate: expect undefined, not null

Full Changelog: 2.1.1...3.0.0