cthreads 0.2.1

[K-T0BIAS]

PyPI: cthreads and cthreads-gpu are on 0.2.1.

What this release is about

0.2.1 fixes a packaging bug from 0.2.0: wheels shipped _ext but not the kernel C++ headers, so @Thread JIT failed after pip install with missing shared_host.hpp. Editable checkouts still worked, which hid the issue. Upgrade:

pip install -U "cthreads>=0.2.1"
# or, for Vulkan @Gpu (do not also install cthreads):
pip install -U "cthreads-gpu>=0.2.1"