Removed greedy matching from a regex to address DOS concern. (opensea…

…rch-project#1006)

Signed-off-by: Chris Helma <chelma+github@amazon.com>

RFS/src/main/java/org/opensearch/migrations/bulkload/common/InvalidResponse.java

@@ -17,7 +17,7 @@
 
 @Slf4j
 public class InvalidResponse extends RfsException {
-    private static final Pattern unknownSetting = Pattern.compile("unknown setting \\[(.+)\\].+");
+    private static final Pattern unknownSetting = Pattern.compile("unknown setting \\[(.+?)\\].+");
     private static final ObjectMapper objectMapper = new ObjectMapper();
     private final HttpResponse response;