Bump requests from 2.21.0 to 2.31.0 in /python/mqtt

Bumps [requests](https://github.com/psf/requests) from 2.21.0 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@v2.21.0...v2.31.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

python/mqtt/requirements-mqtt.txt

@@ -1,3 +1,3 @@
 pymongo==3.12.1
 paho-mqtt==1.2.3
-requests==2.21.0
+requests==2.31.0