update Navigate properly, and add a changeset noting the router stable update in create-app

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.changeset/clean-camels-sneeze.md

@@ -0,0 +1,12 @@
+---
+'@backstage/create-app': patch
+---
+
+Newly created Backstage repositories now use the stable version 6 of
+`react-router`, just like the main repo does. Please let us know if you find any
+issues with this.
+
+Migrating to the stable version of `react-router` is optional for the time
+being. But if you want to do the same for your existing repository, please
+follow [this
+guide](https://backstage.io/docs/tutorials/react-router-stable-migration).

packages/app/src/App.tsx

@@ -148,7 +148,7 @@ const AppRouter = app.getRouter();
 
 const routes = (
   <FlatRoutes>
-    <Navigate key="/" to="catalog" />
+    <Route path="/" element={<Navigate to="/catalog" />} />
     {/* TODO(rubenl): Move this to / once its more mature and components exist */}
     <Route path="/home" element={<HomepageCompositionRoot />}>
       {homePage}

packages/create-app/templates/default-app/packages/app/src/App.tsx

@@ -58,7 +58,7 @@ const AppRouter = app.getRouter();
 
 const routes = (
   <FlatRoutes>
-    <Navigate key="/" to="catalog" />
+    <Route path="/" element={<Navigate to="/catalog" />} />
     <Route path="/catalog" element={<CatalogIndexPage />} />
     <Route
       path="/catalog/:namespace/:kind/:name"