...and bump smithy-kotlin

Author: ianbotsf

gradle/libs.versions.toml

@@ -11,8 +11,8 @@ coroutines-version = "1.9.0"
 atomicfu-version = "0.25.0"
 
 # smithy-kotlin codegen and runtime are versioned separately
-smithy-kotlin-runtime-version = "1.3.20"
-smithy-kotlin-codegen-version = "0.33.20"
+smithy-kotlin-runtime-version = "1.3.21"
+smithy-kotlin-codegen-version = "0.33.21"
 
 # codegen
 smithy-version = "1.51.0"