Release 0.15 and 0.16 rely on a core > last release LTS.

This prevents the plugin from installing/upgrading on users who use LTS.

The most recent version is the only version that works with a flyweight task and a master with zero executors.

changing the parent to 1.509 and recompiling didn't show any reason to need the newer core version and for maximum compatability plugins should only upversion the core if they really need to.