Fixes version field

Author: yepher

libs/sparkpost-lib/src/main/java/com/sparkpost/Build.java

@@ -3,7 +3,7 @@
 
 public class Build {
 
-    public static final String VERSION = "VERSION_NUMBER";
+    public static final String VERSION = "BUILD_VERSION_NAME";
 
     public static final String BUILD_VERSION = "BUILD_GENERATED_VERSION";