refactor: add @filterable tag to filterable properties

src/things/abstract/creative-work.ts

@@ -32,6 +32,8 @@ export interface SCCreativeWorkWithoutReferences
   extends SCThingWithoutReferences, SCThingThatCanBeOfferedWithoutReferences {
   /**
    * Date the creative work was published
+   *
+   * @filterable
    */
   datePublished?: SCISO8601Date;