v2.8.21-canary.5

<!-- Release notes generated using configuration in .github/release.yml at v2.8.21-canary.5 -->

What's Changed

Changelog

• fix: Add NixOS environment variables to default passthroughs by @anthonyshew in https://github.com/vercel/turborepo/pull/12417
• fix: Resolve security vulnerabilities in tar and rustls-webpki by @anthonyshew in https://github.com/vercel/turborepo/pull/12418

Full Changelog: https://github.com/vercel/turborepo/compare/v2.8.21-canary.4...v2.8.21-canary.5