Bump fastapi from 0.111.1 to 0.112.0 in /backend (#55)

Bumps [fastapi](https://github.com/fastapi/fastapi) from 0.111.1 to 0.112.0.
- [Release notes](https://github.com/fastapi/fastapi/releases)
- [Commits](fastapi/fastapi@0.111.1...0.112.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]