[docs] [issue33071] Document that PyPI no longer requires 'register'

Change by hai shi <shihai1991@126.com>: ---------- pull_requests: +13491 stage: backport needed -> patch review pull_request: https://github.com/python/cpython/pull/13584 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33071> _______________________________________