Outflow requirement for Pyyaml version outdated (installation fails with Cython 3)

Outflow requires a Pyyaml version "~5.4.1" See https://gitlab.com/outflow-project/outflow/-/blob/master/pyproject.toml?ref_type=heads#L42

But this Pyyaml version is very outdated (2021) and the installation of outflow fails (due to this requirement) with current environment, python 3.12 and Cython >= 3