fix(/xAPI/about): Uses extensions (#713)

Author: rinzeb

src/apps/statements/expressPresenter/getAbout.ts

@@ -6,7 +6,7 @@ import catchErrors from './utils/catchErrors';
 export default (config: Config) => {
   return catchErrors(config, async (_req: Request, res: Response): Promise<void> => {
     res.status(200).json({
-      'X-Experience-API-Version': xapiHeaderVersion,
+      extensions: {'X-Experience-API-Version': xapiHeaderVersion},
       version: [xapiHeaderVersion],
     });
   });