* Fix Gradle deprecations
By using test suites, we explicitely configure the relevant dependencies
on the test sourceset. This is not done by merely configuring the test task.
* Switch to maintained version of Shadow
* Update to Gradle 8.14.2
Spiritually indebted to #518 and @alexstaeding.
There's a minor break - we're going up to 3.2.0-SNAPSHOT as the API now compiles against Java 11. But this is more academic in practice.
