Bump serialization from 1.8.1 to 1.9.0 (#307)

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ kotlin = "2.2.21"
 kotest = "6.0.4"
 detekt = "1.23.8"
 okio = "3.15.0"
-serialization = "1.8.1"
+serialization = "1.9.0"
 benchmark = "0.4.14"
 openapi = "2025.5"
 jackson = "2.20.0"