v0.21.0

What's Changed

• fix: expose shell completion subcommand by @iloveitaly in https://github.com/railwayapp/railpack/pull/520
• test: add arm builds by @iloveitaly in https://github.com/railwayapp/railpack/pull/509
• feat: additional mise config and idiomatic version files enabling precompiled ruby support by @iloveitaly in https://github.com/railwayapp/railpack/pull/487
• chore: mise update 2026.3.10 by @github-actions[bot] in https://github.com/railwayapp/railpack/pull/522

Full Changelog: https://github.com/railwayapp/railpack/compare/v0.20.0...v0.21.0