Update kotlin monorepo to v1.9.21

Author: renovate[bot]

android/build.gradle

@@ -8,7 +8,7 @@ buildscript {
         minSdkVersion = 23
         compileSdkVersion = 31
         targetSdkVersion = 31
-        kotlin_version = "1.6.0" // Update this to your version
+        kotlin_version = "1.9.21" // Update this to your version
 
         if (System.properties['os.arch'] == "aarch64") {
             // For M1 Users we need to use the NDK 24 which added support for aarch64