Replace deprecated `egg`

[astariul]

Currently this github-hosted PyPi index uses egg. For example :

github-hosted-pypi/public-hello/index.html

Line 76 in fc5183e

<a href="git+https://github.com/astariul/public-hello@0.1#egg=public-hello-0.1">

As pointed out in #84 (see also astral-sh/uv#2602), using egg distributions is deprecated by pip.

We should use something not deprecated.