about-feature-matrix: pikepdf supports reading labels

[mara004]

pikepdf supports reading labels:
https://pikepdf.readthedocs.io/en/latest/topics/pages.html#accessing-page-labels
https://pikepdf.readthedocs.io/en/latest/api/models.html#pikepdf.Page.label

[github-actions]

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I have read the CLA Document and I hereby sign the CLA

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1 out of 2 committers have signed the CLA.
✅ (JorjMcKie)[https://github.com/JorjMcKie]
❌ @mara004
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[mara004]

I have read the CLA Document and I hereby sign the CLA
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