Update Kotlin

Author: renovate[bot]

Diff for: gradle/libs.versions.toml

@@ -31,9 +31,9 @@ jellyfin-sdk = "1.6.8"
 koin = "4.0.4"
 koin-compose = "4.0.4"
 kotest = "5.9.1"
-kotlin = "2.0.21"
-kotlinx-coroutines = "1.9.0"
-kotlinx-serialization = "1.7.3"
+kotlin = "2.1.20"
+kotlinx-coroutines = "1.10.2"
+kotlinx-serialization = "1.8.1"
 markwon = "4.6.2"
 mockk = "1.13.17"
 slf4j-timber = "0.0.4"