gh-36161: Upgrade pplpy to 0.8.9
Upgrade the standard package pplpy to version 0.8.9 (released on PyPI
https://pypi.org/project/pplpy/0.8.9/)
### :memo: Checklist
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URL: https://github.com/sagemath/sage/pull/36161
Reported by: Vincent Delecroix
Reviewer(s):
