Publish sdist with releases

首先检查仓库的打包和发布配置，找出构建和发布 binary wheels 的位置。确认如何将 sdist 添加到该流程中，然后验证某个 release 会将 source tarball 与现有的 wheels 一并发布，并且可以使用它在不受支持的平台上构建该软件包。

Would a change to also make a sdist tarball get published for releases be accepted?

Currently the abi3 binary wheels are great (much better than a bunch of CPython interpreter version specific wheels), though it doesn't give a way for people to install the wheel that are using PyPy. Alternate pip indexes for specific platforms not supported by PyPI such as piwheels.org and Pyodide also need an sdist in order to build wheels from PyPI.

Having an sdist also means I can install die-python on systems with CPUs that currently don't have binary wheels published, such as ppcle64 and risc-v systems. For releasing other software that depends on die-python this is particularly helpful, since PyPI doesn't allow uploading packages that have dependencies installed via direct git/http URLs.