add CREDITS

Author: k163377

release-notes/CREDITS-2.x

@@ -22,6 +22,7 @@ wrongwrong (k163377@github)
 * #456: Refactor KNAI.findImplicitPropertyName()
 * #449: Refactor AnnotatedMethod.hasRequiredMarker()
 * #521: Fixed lookup of instantiators
+* #527: Improvements to serialization of `value class`.
 
 Dmitri Domanine (novtor@github)
 * Contributed fix for #490: Missing value of type JsonNode? is deserialized as NullNode instead of null