The cache-cleanup API has changed, so the init-script that worked with
Gradle 8.9 no longer works with 8.11.
We now provision and use Gradle 8.11 for cache cleanup.
This provides a band-aid fix for #417 but that issue will still impact
any build configured to run with Gradle > 8.11
Gradle 8.8 introduces new features that allow us to avoid using
timestamp manipulation to force the cleanup of the Gradle User Home directory.
This solution is simpler and more robust, but relies on Gradle 8.8+ always being
used for the cache cleanup operation.
Fixes#24