community/py3-thinc: remove due to no cython 3 support
This package requires cython<3.0 and we need cython 3 because cython 0 tests does not run on python 3.12.
Nothing else depends on py3-thinc so remove. We can re-add this package when upstream adds support for cython 3 if needed.
ref: https://github.com/explosion/thinc/blob/3aae298d32adc167ac57e0791a5a8c0544b1e8a5/pyproject.toml#L4 ref: https://github.com/cython/cython/pull/6135