[16.0][IMP] report_qweb_pdf_watermark: support pypdf >= 2.0

[hbrunn]

see https://pypdf2.readthedocs.io/en/3.0.0/user/migration-1-to-2.html

[risto42]

Well, according to https://pypdf2.readthedocs.io/en/3.x/

PyPDF2 is deprecated, please use pypdf

[thomaspaulb]

PyPDF2 is deprecated, please use pypdf

Right, but all this also applies to version 2 of pypdf: https://pypdf.readthedocs.io/en/latest/user/migration-1-to-2.html

[risto42]

PyPDF2 is deprecated. PyPDF can support OCB v16 minimal version of python (3.7) with a version prior to PyPDF-5.0.0,
no problem with recent versions.
There is no reason to put off a trivial migration complicating things further.
This applies for all PyPDF2 usage in OCA as well as in OCB.

[thomaspaulb]

@hbrunn It makes sense - why are we still importing pypdf2 and not pypdf ?