Update kotlinx.serialization to v1.7.3

Author: renovate[bot]

gradle/libs.versions.toml

@@ -4,7 +4,7 @@ compileSdk = "34"
 http4k = "4.48.0.0"
 kotlin = "2.0.20"
 kotlinx-coroutines = "1.9.0"
-kotlinx-serialization = "1.7.2"
+kotlinx-serialization = "1.7.3"
 okHttp = "4.12.0"
 okio = "3.9.1"
 minSdk = "21"