Update kotlin monorepo to v2.0.21

Author: renovate[bot]

gradle/libs.versions.toml

@@ -6,7 +6,7 @@ java-toolchain = "17"
 
 compose = "1.6.11"
 agp = "8.5.2"
-kotlin = "2.0.20"
+kotlin = "2.0.21"
 publish = "0.29.0"
 api-validator = "0.16.3"
 atomicfu = "0.22.0"