release(turborepo): 2.8.15 (#12223)
## Release v2.8.15
Versioned docs: https://v2-8-15.turborepo.dev
### Changes
- ci: Split build and test into separate jobs for macOS and Ubuntu
(#12216) (`86dd435`)
- release(turborepo): 2.8.15-canary.14 (#12221) (`587cf97`)
- ci: Remove Rust test coverage infrastructure (#12219) (`8c5dca2`)
- fix: Replace Chocolatey with direct download for Windows capnproto
setup (#12222) (`d16ca9c`)
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Co-authored-by: Turbobot <turbobot@vercel.com>