Build Cache for Xcode v0.15.1

[system]

What’s Changed

• Bump CLI to v3.1.0 — CI-safe auth file backend (#421). Full changelog: Release v3.1.0 · bitrise-io/bitrise-build-cache-cli · GitHub

Release 0.15.1 · bitrise-steplib/bitrise-step-activate-build-cache-for-xcode