Bump requests from 2.26.0 to 2.27.1 in /backend

Bumps [requests](https://github.com/psf/requests) from 2.26.0 to 2.27.1.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](https://github.com/psf/requests/compare/v2.26.0...v2.27.1)

---
updated-dependencies:
- dependency-name: requests
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

backend/requirements.txt

@@ -6,5 +6,5 @@ python-engineio==3.14.2
 python-socketio==4.6.1
 six==1.16.0
 pytest==6.2.5
-requests==2.26.0
+requests==2.27.1
 discord-webhook==0.14.0