deps: update bcrypt requirement from 0.17 to 0.19 in /backend

Updates the requirements on [bcrypt](https://github.com/Keats/rust-bcrypt) to permit the latest version.
- [Commits](Keats/rust-bcrypt@v0.17.0...v0.19.0)

---
updated-dependencies:
- dependency-name: bcrypt
  dependency-version: 0.19.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

backend/Cargo.toml

@@ -27,7 +27,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 sqlx = { version = "0.8", features = ["runtime-tokio-rustls", "sqlite"] }
 jsonwebtoken = { version = "10.2", features = ["use_pem", "rust_crypto"] }
-bcrypt = "0.17"
+bcrypt = "0.19"
 chrono = { version = "0.4", features = ["serde"] }
 dotenv = "0.15"
 tracing = "0.1"