- open api: fix minor upgrade generating breaking changes

Author: jknack

modules/jooby-openapi/src/main/java/io/jooby/internal/openapi/projection/SchemaPruner.java

@@ -120,7 +120,9 @@ private static void copyMetadata(Schema<?> source, Schema<?> target) {
     target.setTitle(source.getTitle());
     target.setDescription(source.getDescription());
     target.setFormat(source.getFormat());
-    target.setDefault(source.getDefault());
+    if (source.getDefaultSetFlag()) {
+      target.setDefault(source.getDefault());
+    }
     if (source.getExample() != null) {
       target.setExample(source.getExample());
     }