pip(deps): bump fastapi from 0.115.12 to 0.118.0 in /backend (#119)

Bumps [fastapi](https://github.com/fastapi/fastapi) from 0.115.12 to 0.118.0.
- [Release notes](https://github.com/fastapi/fastapi/releases)
- [Commits](fastapi/fastapi@0.115.12...0.118.0)

---
updated-dependencies:
- dependency-name: fastapi
  dependency-version: 0.118.0
  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]

backend/pyproject.toml

@@ -6,7 +6,7 @@ authors = ["Your Name <[email protected]>"]
 
 [tool.poetry.dependencies]
 python = "^3.9"
-fastapi = "^0.116.1"
+fastapi = "^0.118.0"
 pydantic = "^2.10.5"
 google-cloud-firestore = "^2.3.4"
 google-cloud-functions = "^1.4.0"