Bump pypdf

Bumps the pip group with 1 update in the /src/ghosts.shadows/src directory: [pypdf](https://github.com/py-pdf/pypdf).


Updates `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: direct:production
  dependency-group: pip
...

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

Author: dependabot[bot]

src/ghosts.shadows/src/requirements.txt

@@ -8,7 +8,7 @@ Requests==2.32.4
 torch==2.8.0
 transformers==4.53.0
 docx2txt==0.8
-pypdf==6.1.3
+pypdf==6.4.0
 chromadb==0.4.24
 tqdm
 pipdeptree