Bump pypdf from 6.1.3 to 6.4.0

Bumps [pypdf](https://github.com/py-pdf/pypdf) from 6.1.3 to 6.4.0.
- [Release notes](https://github.com/py-pdf/pypdf/releases)
- [Changelog](https://github.com/py-pdf/pypdf/blob/main/CHANGELOG.md)
- [Commits](py-pdf/pypdf@6.1.3...6.4.0)

---
updated-dependencies:
- dependency-name: pypdf
  dependency-version: 6.4.0
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -108,7 +108,7 @@ pygments==2.19.2
     # via mkdocs-material
 pymdown-extensions==10.16.1
     # via mkdocs-material
-pypdf==6.1.3
+pypdf==6.4.0
     # via mkdocs-exporter
 python-dateutil==2.9.0.post0
     # via