Bump serde from 1.0.204 to 1.0.205 in /backend in the cargo group

Bumps the cargo group in /backend with 1 update: [serde](https://github.com/serde-rs/serde).


Updates `serde` from 1.0.204 to 1.0.205
- [Release notes](https://github.com/serde-rs/serde/releases)
- [Commits](serde-rs/serde@v1.0.204...v1.0.205)

---
updated-dependencies:
- dependency-name: serde
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: cargo
...

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