v0.21.0

Improvements

• feat: add --patch-existing option to CLI upsert [#76] @themightychris

Technical

• feat(ci): rename workflow to publish website @themightychris
• fix(mkdocs): quote config yaml @themightychris
• feat(ci): add workflow to publish to npm @themightychris
• feat(ci): add automated release workflow @themightychris