Update kotlinx.serialization to v1.8.1

Author: renovate[bot]

gradle/libs.versions.toml

@@ -17,7 +17,7 @@ kotlin = "2.1.20"
 okhttp = "3.14.9"
 protobuf = "3.25.6"
 robovm = "2.3.14"
-kotlinx-serialization = "1.8.0"
+kotlinx-serialization = "1.8.1"
 autoService = "1.1.1"
 incap = "1.0.0"
 jackson = "2.18.3"