Build Cache for Gradle v2.20.17

Changelog
1

What’s Changed

  • Bump bitrise-build-cache CLI to v2.8.13 — SSW-3019: the gradle-mirrors init script now captures the native-runtime failure cause behind the Robolectric NoSuchFieldError @ DeviceConfig cascade (NPE @ DefaultNativeRuntimeLoader:201): per-jar ICU-entry audit, JDK 17+ gated -Xlog:library, and testLogging FULL on failed tests. Opt-out (BITRISE_ROBOLECTRIC_JAR_AUDIT=false); never fails a build.