Add PyO3 iterator fix references

[cookesan]

Summary

• add the PyO3 iterator fix commit reference
• add the PyO3 0.29.0 fixed release reference

Validation

• confirmed the advisory fixes crates.io package pyo3 in 0.29.0
• confirmed the PyO3 fix commit and v0.29.0 release URLs return HTTP 200
• confirmed the v0.29.0 release notes list the BoundTupleIterator and BoundListIterator nth_back out-of-bounds read fix
• confirmed v0.29.0 contains fix commit 3d48a540572a86548a8f670ea96fa486036d476a
• confirmed crates.io API metadata for pyo3 0.29.0 resolves, is not yanked, and lists newest version 0.29.0
• ran jq empty on the advisory JSON
• ran git diff --check