make JsonUtils class final

Author: innokenty

proxy/src/test/java/ru/qatools/gridrouter/utils/JsonUtils.java

@@ -16,7 +16,10 @@
 /**
  * @author Innokenty Shuvalov [email protected]
  */
-public class JsonUtils {
+public final class JsonUtils {
+
+    private JsonUtils() {
+    }
 
     public static JsonCapabilities buildJsonCapabilities(DesiredCapabilities capabilities)
             throws IOException {