Update Rust crate async-nats to 0.43.0

Author: renovate[bot]

Cargo.toml

@@ -12,7 +12,7 @@ futures-lite = "2.6.0"
 rand = "0.9.1"
 base64 = "0.22.1"
 env_logger = "0.11.8"
-async-nats = "0.42.0"
+async-nats = "0.43.0"
 prost = "0.14.1"
 tonic-health = "0.14.1"
 tonic = "0.14.1"