Update release notes wrt #707

Author: k163377

release-notes/CREDITS-2.x

@@ -21,6 +21,7 @@ kkurczewski
 * #689: Add KotlinDuration support
 
 WrongWrong (@k163377)
+* #707: Changed to use default argument on null if JsonSetter(nulls = Nulls.SKIP) is specified.
 * #700: Reduce the load on the search process for serializers
 * #687: Optimize and Refactor KotlinValueInstantiator.createFromObjectWith
 * #686: Add KotlinPropertyNameAsImplicitName option

release-notes/VERSION-2.x

@@ -18,6 +18,7 @@ Co-maintainers:
 
 2.16.0 (not yet released)
 
+#707: If JsonSetter(nulls = Nulls.SKIP) is specified, the default argument is now used when null.
 #700: Reduce the load on the search process for serializers.
 #689: Added UseJavaDurationConversion feature.
  By enabling this feature and adding the Java Time module, Kotlin Duration can be handled in the same way as Java Duration.