chore(deps): bump serde_json from 1.0.79 to 1.0.81 in /backend (#26)

Bumps [serde_json](https://github.com/serde-rs/json) from 1.0.79 to 1.0.81.
- [Release notes](https://github.com/serde-rs/json/releases)
- [Commits](https://github.com/serde-rs/json/compare/v1.0.79...v1.0.81)

---
updated-dependencies:
- dependency-name: serde_json
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Ruben Fiszel <ruben@rubenfiszel.com>

backend/Cargo.lock

@@ -2724,9 +2724,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.79"
+version = "1.0.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8e8d9fa5c3b304765ce1fd9c4c8a3de2c8db365a5b91be52f186efc675681d95"
+checksum = "9b7ce2b32a1aed03c558dc61a5cd328f15aff2dbc17daad8fb8af04d2100e15c"
 dependencies = [
  "indexmap",
  "itoa 1.0.1",