Update jackson to v2.12.2

Author: renovate-bot

games-server/build.gradle

@@ -1,7 +1,7 @@
 buildscript {
     ext.kotlin_version = "1.3.61"
     ext.jupiter_version = "5.7.0"
-    ext.jackson_version = "2.11.3"
+    ext.jackson_version = "2.12.2"
 
     repositories {
         mavenCentral()