Bump requests from 2.27.1 to 2.28.1 in /Backend

Bumps [requests](https://github.com/psf/requests) from 2.27.1 to 2.28.1.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](psf/requests@v2.27.1...v2.28.1)

---
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

@@ -3,7 +3,7 @@ PyYAML==6.0
 gevent==21.12.0
 Flask-Cors==3.0.10
 pyodbc==4.0.32
-requests==2.27.1
+requests==2.28.1
 uuid==1.30
 mysql-connector-python==8.0.27
 cryptography==37.0.1