Update dependency org.jetbrains.kotlinx:atomicfu to v0.21.0

Author: renovate[bot]

gradle/libs.versions.toml

@@ -53,7 +53,7 @@ kotlin = "1.8.10"
 kotlinx-binary-compatibility = "0.13.2"
 kotlinx-coroutines = "1.7.1"
 kotlinx-serialization-json = "1.5.1"
-kotlinx-atomicfu = "0.17.2"
+kotlinx-atomicfu = "0.21.0"
 
 ktlint = "0.49.1"
 ktlint-gradle = "0.1.7"