Bump transformers in /mobile/examples/question_answering/android (#412)

Bumps [transformers](https://github.com/huggingface/transformers) from 4.36.0 to 4.38.0.
- [Release notes](https://github.com/huggingface/transformers/releases)
- [Commits](huggingface/transformers@v4.36.0...v4.38.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

mobile/examples/question_answering/android/prepare_model.requirements.txt

@@ -1,5 +1,5 @@
 onnxruntime
 onnxruntime-extensions
 onnx
-transformers==4.36.0
+transformers==4.38.0
 torch==1.13.1