Support python 3.13

[TomeHirata]

Resolve #8253

[Copilot]

Pull Request Overview

This PR updates the package metadata to officially support Python 3.13 by adjusting the version requirement.

• Bumps the upper bound in requires-python to <3.14
• Ensures the project can be installed on Python 3.13 environments

[chenmoneygithub]

Before merging, can we run a quick test locally on py 3.14? Feel free to leave this on me, I can handle it tomorrow.

[TomeHirata]

I exclude 3.14 due to the license error in xxhash. https://github.com/ifduyue/python-xxhash/blob/b3cc1b8bc1c27da0a0ed8bce2c1d92ae86966961/setup.py#L48

$ uv venv --python 3.14
$ uv sync --dev --extra dev 

Resolved 148 packages in 1.23s
  × Failed to build `xxhash==3.5.0`
  ├─▶ The build backend returned an error
  ╰─▶ Call to `setuptools.build_meta.build_wheel` failed (exit status: 1)

      [stdout]
      running bdist_wheel
      running build
      running build_py
      copying xxhash/version.py -> build/lib.macosx-11.0-arm64-cpython-314/xxhash
      copying xxhash/__init__.py -> build/lib.macosx-11.0-arm64-cpython-314/xxhash
      copying xxhash/__init__.pyi -> build/lib.macosx-11.0-arm64-cpython-314/xxhash
      copying xxhash/py.typed -> build/lib.macosx-11.0-arm64-cpython-314/xxhash
      running build_ext
      building '_xxhash' extension
      cc -fno-strict-overflow -Wsign-compare -Wunreachable-code -DNDEBUG -g -O3 -Wall -arch arm64 -mmacosx-version-min=11.0 -Wno-nullability-completeness
      -Wno-expansion-to-defined -Wno-undef-prefix -fPIC -Ideps/xxhash -I/Users/tomu.hirata/.cache/uv/builds-v0/.tmpYajWUL/include
      -I/Users/tomu.hirata/.local/share/uv/python/cpython-3.14.0a6-macos-aarch64-none/include/python3.14 -c deps/xxhash/xxhash.c -o
      build/temp.macosx-11.0-arm64-cpython-314/deps/xxhash/xxhash.o

      [stderr]
      /Users/tomu.hirata/.cache/uv/builds-v0/.tmpYajWUL/lib/python3.14/site-packages/setuptools/dist.py:759: SetuptoolsDeprecationWarning: License classifiers
      are deprecated.
      !!

              ********************************************************************************
              Please consider removing the following classifiers in favor of a SPDX license expression:

              License :: OSI Approved :: BSD License

              See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for details.
              ********************************************************************************

      !!
        self._finalize_license_expression()
      In file included from deps/xxhash/xxhash.c:43:
      deps/xxhash/xxhash.h:496:10: fatal error: cannot open file '/usr/local/include/stddef.h': Permission denied
        496 | #include <stddef.h>   /* size_t */
            |          ^
      1 error generated.
      error: command '/usr/bin/cc' failed with exit code 1

      hint: This usually indicates a problem with the package or the build environment.
  help: `xxhash` (v3.5.0) was included because `dspy` (v2.6.24) depends on `datasets` (v3.5.0) which depends on `xxhash`

[TomeHirata]

I've confirmed basic path works ok and all tests pass in python 3.13.