v0.21.0

What's Changed

• perf(executor): start each target as soon as its dependencies finish by @calvin-archastro in #155
• perf(aster-srv): classify from each test's latest result, not its history by @calvin-archastro in #156
• chore: release v0.21.0 by @calvin-archastro in #157

Full Changelog: v0.20.0...v0.21.0