py.typed marker file not included in published wheel

Related to #223

The changes from #224 should have resulted in the py.typed marker file being included in the published wheel (following the [instructions in the setuptools docs](https://setuptools.pypa.io/en/latest/userguide/datafiles.html#package-data) and the [example package](https://github.com/emmatyping/pep-561) included in [PEP561](https://peps.python.org/pep-0561/)

When I build the package locally, the file is included; however, the layout I get in the locally built wheel is slightly different than the published version, so there is definitely some configuration or setuptools/wheel version difference.

先检查包和构建配置，然后将本地构建的 wheel 与已发布的 wheel 进行比较，并查看 issue 中链接的 setuptools 数据文件说明。使用项目当前的构建工具复现这一差异；当已发布的 wheel 包含位于预期包布局中的 py.typed 标记时，即表示完成。

由索引模型根据 Issue 内容生成。