Bump requests in /test/sagemaker_tests/mxnet/training

Bumps [requests](https://github.com/psf/requests) from 2.25.1 to 2.31.0.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](psf/requests@v2.25.1...v2.31.0)

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

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

Author: dependabot[bot]

test/sagemaker_tests/mxnet/training/requirements.txt

@@ -5,7 +5,7 @@ pytest==5.3.5
 pytest-cov
 pytest-rerunfailures==9.0
 pytest-xdist
-requests==2.25.1
+requests==2.31.0
 urllib3>=1.26.6
 mock
 sagemaker