Update requests requirement from ~=2.25 to ~=2.31 in /frontend

Updates the requirements on [requests](https://github.com/psf/requests) to permit the latest version.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](psf/requests@v2.25.0...v2.31.0)

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

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

frontend/requirements.txt

@@ -3,4 +3,4 @@ flasgger~=0.9.4
 flask_restful~=0.3.10
 elasticsearch~=7.0
 spacy~=2.2
-requests~=2.25
+requests~=2.31