Update kotlin monorepo to v1.9.0

Author: renovate[bot]

buildSrc/build.gradle.kts

@@ -38,7 +38,7 @@ dependencies {
     implementation("com.diffplug.spotless:spotless-plugin-gradle:6.12.0")
     implementation("org.jetbrains.dokka:dokka-gradle-plugin:1.7.20")
     implementation("dev.floofy.commons:gradle:2.4.1")
-    implementation(kotlin("serialization", "1.7.22"))
-    implementation(kotlin("gradle-plugin", "1.7.22"))
+    implementation(kotlin("serialization", "1.9.0"))
+    implementation(kotlin("gradle-plugin", "1.9.0"))
     implementation(gradleApi())
 }