PyPI currently only supports GitHub since they were one of the first providers that had the necessary functionality to make this possible, however it is based on open standards and we have plans to add additional providers in the future (Google Cloud, ActiveState, GitLab, CircleCI and Cirrus CI are in the works.)
The goal is to make “project creation” (or publishing the first release) happen exactly the same way as publishing additional releases, and not require special steps, workflows, tokens, or interfaces just because it’s the first release.