0.5.6 cosmetics and versions upgrade, JVM target to 11 for better android compatibility

README.md

@@ -19,7 +19,7 @@ repositories {
   maven("https://gitea.sergeych.net/api/packages/SergeychWorks/maven")
 }
 dependencies {
-  import("net.sergeych:crypto2:0.5.5")  
+  import("net.sergeych:crypto2:0.5.6")  
 }
 ```