it is not that simple, Odoo code still depends on the old unmaintained python-pypdf

However, there is an easy workaround : create a fake python-pdf package and install python-pyPdf from Pipy (Python repository). All of this will be done as root :

install equivs to create fake packages and python-pipto install package from Python repository
run equivs-control python-pypdf, this will create and populate the file python-pypdf
edit the file like below (dot and space under "Description" are mandatory) :
Section: python
Package: python-pypdf
Version: 1.13
Description: fake package to provide python-pypdf
 python-pypdf will need to be installed with pip
 .
 python-pypdf2  does not provide python-pypdf
run equivs-build python-pypdf this will create the fake package python-pypdf_1.13_all.deb
install the package with dpkg -i python-pypdf_1.13_all.deb
run pip install pyPdf
restart Odoo