build(deps): bump async-trait in /atcoder-problems-backend

Bumps [async-trait](https://github.com/dtolnay/async-trait) from 0.1.56 to 0.1.57.
- [Release notes](https://github.com/dtolnay/async-trait/releases)
- [Commits](dtolnay/async-trait@0.1.56...0.1.57)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

atcoder-problems-backend/Cargo.lock

@@ -9,7 +9,7 @@ publish = false
 
 [dependencies]
 sqlx = { version = "0.6.1", features = ["postgres", "runtime-tokio-rustls"] }
-async-trait = "0.1.56"
+async-trait = "0.1.57"
 serde = { version = "1.0", features = ["derive"] }
 uuid = { version = "1.1", features = ["serde", "v4"] }
 anyhow = "1.0"