v0.8.0-alpha.21

What's Changed

• [ci] Don't fail fast when rolling pinned versions by @joshlf in #1628
• [Cargo.toml] Make crate description consistent with README by @joshlf in #1627
• [ci] Roll toolchains using filepath package names by @joshlf in #1630
• Support deriving traits on data-carrying enums by @djkoloski in #879
• Release 0.8.0-alpha.21 by @google-pr-creation-bot in #1635

Full Changelog: v0.8.0-alpha.20...v0.8.0-alpha.21