PySide6-Essentials not available on pypi

[martinclemens]

Downloading the 4.2.0 tarball and calling pip install . leads to

ERROR: Could not find a version that satisfies the requirement PySide6-Essentials~=6.4 (from extrap==4.2.0) (from versions: none)
ERROR: No matching distribution found for PySide6-Essentials~=6.4 (from extrap==4.2.0)

Replacing the dependency of PySide6-Essentials in setup.py by PySide6~=6.2.4 (the most recent available version via pip) solves this issue.