v0.21.0

Changelog

• fd13eb8 release: v0.21.0
• 975d922 docs(changelog): roll accumulated Unreleased into 0.17.0–0.21.0 sections (#189)
• 8ce5bd0 feat(spec): post/v1 second pre-adoption amendment — drop topics, narrow format, add publishedAt (#188)
• 930a5ea feat(index): add ?nameContains= substring filter on the identity index (#187)
• 527d56e fix(web-relay): re-export IndexCredentialRow from package root (#186)