pyenv v2.7.3

What's Changed

• CI: add_version enhancements by @macayu17 in https://github.com/pyenv/pyenv/pull/3475
• Add CPython 3.15.0b3 by @pyenv-bot[bot] in https://github.com/pyenv/pyenv/pull/3479

Full Changelog: https://github.com/pyenv/pyenv/compare/v2.7.2...v2.7.3