Bump certifi from 2021.10.8 to 2022.12.7 in /backend

Bumps [certifi](https://github.com/certifi/python-certifi) from 2021.10.8 to 2022.12.7.
- [Release notes](https://github.com/certifi/python-certifi/releases)
- [Commits](certifi/python-certifi@2021.10.08...2022.12.07)

---
updated-dependencies:
- dependency-name: certifi
  dependency-type: indirect
...

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