message: Add RelationshipConstraint to index exports.
diff: @@ -8,7 +8,7 @@ export { default as SchemaChild } from "./Metadata/SchemaChild";
  export { default as ECClass, StructClass } from "./Metadata/Class";
  export { default as EntityClass } from "./Metadata/EntityClass";
  export { default as MixinClass } from "./Metadata/MixinClass";
  -export { default as RelationshipClass } from "./Metadata/RelationshipClass";
  +export { default as RelationshipClass, RelationshipConstraint } from "./Metadata/RelationshipClass";
  export { default as CustomAttributeClass } from "./Metadata/CustomAttributeClass";
  export { default as Enumeration, Enumerator } from "./Metadata/Enumeration";
  export { default as KindOfQuantity } from "./Metadata/KindOfQuantity";
  