Update Kotlin version for workflow preprocessing to 2.1.20

Author: Vampire

gradle/libs.versions.toml

@@ -28,7 +28,7 @@ build-snakeyaml = "2.0"
 kotlin = "2.0.21"
 kotlinx-coroutines = "1.6.4"
 ktor = "3.0.0"
-workflows-kotlin = "2.1.10"
+workflows-kotlin = "2.1.20"
 
 [libraries]
 actions-cache = { module = "actions:cache", version.ref = "actions-cache" }