Bump requests from 2.25.1 to 2.31.0 in /samples/python

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>

samples/python/Pipfile

@@ -6,7 +6,7 @@ name = "pypi"
 [packages]
 fastapi = "==0.63.0"
 uvicorn = "==0.11.8"
-requests = "==2.25.1"
+requests = "==2.31.0"
 pydantic = "==1.7.4"
 dataclasses-json = "==0.5.2"
 starlette = "==0.13.6"