use PropertyNamingStrategy's static field instead of new its subclass

bypass the potential deadlock when PropertyNamingStrategy class initialization
see: FasterXML/jackson-databind#2715

Author: fangwentong

ksc-sdk-java-core/src/main/java/com/ksc/transform/JsonErrorUnmarshaller.java

@@ -17,7 +17,7 @@
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.PropertyNamingStrategy.PascalCaseStrategy;
+import com.fasterxml.jackson.databind.PropertyNamingStrategy;
 import com.ksc.KscServiceException;
 import com.ksc.annotation.SdkInternalApi;
 import com.ksc.annotation.ThreadSafe;
@@ -34,7 +34,7 @@ public class JsonErrorUnmarshaller extends AbstractErrorUnmarshaller<JsonNode> {
 
     private static final ObjectMapper MAPPER = new ObjectMapper().configure(
             DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false).setPropertyNamingStrategy(
-            new PascalCaseStrategy());
+            PropertyNamingStrategy.PASCAL_CASE_TO_CAMEL_CASE);
 
     private final String handledErrorCode;