add roadmap with release notes to first level.

webpage/sidebars.ts

@@ -54,11 +54,8 @@ const sidebars: SidebarsConfig = {
       label: 'Integration & Extensibility',
       items: [{ type: "autogenerated", dirName: "integration-and-extensibility" }]
     },
-    {
-      type: 'category',
-      label: 'Changelog & Releases',
-      items: [{ type: "autogenerated", dirName: "changelog-and-releases" }]
-    },
+    'release-notes',
+    'roadmap',
   ],
   apiSidebar: require("./docs/api/sidebar.js"),
 };