docs/Changelog: 9.0 release notes are missing

The changelog for tenacity latest at https://tenacity.readthedocs.io/en/latest/changelog.html shows only release notes up to 8.2.2 while the released version on PyPI and on GitHub is 9.0.0.

This seems wrong to me.