v2.8.21-canary.15

<!-- Release notes generated using configuration in .github/release.yml at v2.8.21-canary.15 -->

What's Changed

Changelog

• refactor: Move cache hit SHA context to verbose logging by @mehulkar in https://github.com/vercel/turborepo/pull/12435

Full Changelog: https://github.com/vercel/turborepo/compare/v2.8.21-canary.14...v2.8.21-canary.15