Bump requests in /lambdas/OpensearchAnomalyDetector

Bumps [requests](https://github.com/psf/requests) from 2.28.1 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@v2.28.1...v2.31.0)

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

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

lambdas/OpensearchAnomalyDetector/requirements.txt

@@ -1,3 +1,3 @@
 boto3==1.26.75
 requests-aws4auth==1.1.2
-requests==2.28.1
+requests==2.31.0