Log Message:
py-pikepdf: updated to 9.1.0

v9.1.0

- Fixed a potential resource leak if we opened a file to read it as a PDF but
  it was not a valid PDF.
- When overwriting an existing PDF with ``Pdf.save()``, pikepdf now attempts to
  retain the original file permissions and ownership.
- Fixed missing return type for PageList.Extend. :issue:`592`
- Fixed tests on Python 3.13 pre-release. Thanks @QuLogic.
- Changed all references of "QPDF" to "qpdf", its new \ 
spelling. Thanks @m-holger.