Increase key size

[perguth]

Fixes https://github.com/choojs/choo/issues/715

Choose one: is this a 🐛 bug fix, a 🙋 feature, or a 🔦 documentation change?

Checklist

• [ ] tests pass
• [ ] tests and/or benchmarks are included
• [ ] documentation is changed or added

Context

Semver Changes