Make CloudFormationResponse public as it is needed for subclass mockmaker.

Author: phipag

powertools-cloudformation/src/main/java/software/amazon/lambda/powertools/cloudformation/CloudFormationResponse.java

@@ -46,7 +46,7 @@
  * <p>
  * This class is thread-safe provided the SdkHttpClient instance used is also thread-safe.
  */
-class CloudFormationResponse {
+public class CloudFormationResponse {
 
     private static final Logger LOG = LoggerFactory.getLogger(CloudFormationResponse.class);
     private final SdkHttpClient client;