modify version

Author: zhang0125

framework/src/main/java/org/tron/program/Version.java

@@ -4,7 +4,7 @@ public class Version {
 
   public static final String VERSION_NAME = "GreatVoyage-v4.1.3-199-gc433410f8";
   public static final String VERSION_CODE = "15510";
-  private static final String VERSION = "4.2.0";
+  private static final String VERSION = "4.2.1";
 
   public static String getVersion() {
     return VERSION;