Align evaluate version to 0.4.5 in question-answering requirements

[gplutop7]

This PR updates the evaluate package version in
examples/question-answering/requirements.txt from 0.4.3 to 0.4.5
to align it with examples/text-classification/requirements.txt
on the master_next branch.

Background:

• The previous mismatch between 0.4.3 (QA) and 0.4.5 (Text Classification)
  caused dependency conflicts in CI:
  Cannot install evaluate==0.4.3 and evaluate==0.4.5.

Changes:

• Updated evaluate==0.4.3 → evaluate==0.4.5 in question-answering requirements.
• No functional code changes, only dependency alignment.

This resolves the version conflict reported in the
Test_pytorch_training_tests_gaudi2_asic_8cards_topology_8cards_master_next
job and ensures consistent dependency management across examples.