Bump serde_json from 1.0.80 to 1.0.81

Bumps [serde_json](https://github.com/serde-rs/json) from 1.0.80 to 1.0.81.
- [Release notes](https://github.com/serde-rs/json/releases)
- [Commits](https://github.com/serde-rs/json/compare/v1.0.80...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>

Cargo.toml

@@ -21,7 +21,7 @@ rocket_contrib = { version = "0.4.5", features = ["json"] }
 rocket_i18n = "0.4.1"
 scheduled-thread-pool = "0.2.2"
 serde = "1.0"
-serde_json = "1.0.80"
+serde_json = "1.0.81"
 shrinkwraprs = "0.3.0"
 validator = { version = "0.15", features = ["derive"] }
 webfinger = "0.4.1"