Update Rust crate resend-rs to 0.16.0

Author: oxide-renovate[bot]

Cargo.lock

@@ -60,7 +60,7 @@ reqwest = { version = "0.12", default-features = false, features = ["json", "str
 reqwest-middleware = "0.4"
 reqwest-retry = "0.7"
 reqwest-tracing = "0.5"
-resend-rs = { version = "0.15.0", default-features = false, features = ["rustls-tls"] }
+resend-rs = { version = "0.16.0", default-features = false, features = ["rustls-tls"] }
 ring = "0.17.14"
 rsa = "0.9.8"
 rustfmt-wrapper = "0.2.1"