Bump pypdf2 from 1.26.0 to 1.27.9 in /Python/PDF_watermaker

Bumps [pypdf2](https://github.com/py-pdf/PyPDF2) from 1.26.0 to 1.27.9.
- [Release notes](https://github.com/py-pdf/PyPDF2/releases)
- [Changelog](https://github.com/py-pdf/pypdf/blob/1.27.9/CHANGELOG)
- [Commits](py-pdf/pypdf@1.26.0...1.27.9)

---
updated-dependencies:
- dependency-name: pypdf2
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>