chore: update pypdf dependency in worker
Should fix https://github.com/huggingface/datasets-server/security/dependabot/200
But not sure where exactly we use this library, according to pypi page pypdf2 is now pypdf (Not sure if this will break something):
`NOTE: The PyPDF2 project is going back to its roots. PyPDF2==3.0.X will be the last version of PyPDF2. Development will continue with [pypdf==3.1.0](https://pypi.org/project/pyPdf/)` 
chore: update pypdf dependency in worker: Should fix https://github.com/huggingface/datasets-server/security/dependabot/200
But not sure where exactly we use this library, according to pypi page pypdf2 is now pypdf (Not sure if this will break something):
`NOTE: The PyPDF2 project is going back to its roots. PyPDF2==3.0.X will be the last version of PyPDF2. Development will continue with [pypdf==3.1.0](https://pypi.org/project/pyPdf/)` 