Update Rust crate regex to 1.12.3

Author: oxide-renovate[bot]

Cargo.lock

@@ -10,7 +10,7 @@ resolver = "2"
 futures = "0.3.31"
 http = "1.4.0"
 matrix-sdk = { version = "0.16.0", default-features = false, features = ["rustls-tls"] }
-regex = "1.12.2"
+regex = "1.12.3"
 ruma = { version = "0.14", features = ["events"] }
 ruma-common = "0.17.0"
 serde = { version = "1.0.228", features = ["derive"] }