Update Rust crate thiserror to 2.0.18

Author: oxide-renovate[bot]

Cargo.lock

@@ -14,6 +14,6 @@ regex = "1.12.2"
 ruma = { version = "0.14", features = ["events"] }
 ruma-common = "0.17.0"
 serde = { version = "1.0.228", features = ["derive"] }
-thiserror = "2.0.17"
+thiserror = "2.0.18"
 tokio = "1.48.0"
 tracing = "0.1.44"