Mention feature/occupancy in 0.3.0 release notes

Author: oleksandr-pavlyk

cuda_core/docs/source/release/0.3.0-notes.rst

@@ -21,6 +21,7 @@ New features
 ------------
 
 - :class:`Kernel` adds :property:`Kernel.num_arguments` and :property:`Kernel.arguments_info` for introspection of kernel arguments. (#612)
+- Add pythonic access to kernel occupancy calculation functions via :property:`Kernel.occupancy`. (#648)
 
 New examples
 ------------