Renamed petstore.json to swagger.json

demo/index.html

@@ -14,7 +14,7 @@
     <script src="dist/redoc.full.js"> </script>
     <script>
       /* init redoc */
-      Redoc.init('petstore.json');
+      Redoc.init('swagger.json');
     </script>
   </body>
 </html>