changesets,create-app: update for createApp split

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/giant-drinks-wave.md

@@ -2,4 +2,4 @@
 '@backstage/dev-utils': patch
 ---
 
-Migrated to using `withDefaults` to pass defaults to `createApp`.
+Migrated to using `@backstage/app-defaults`.

.changeset/hot-walls-fail.md

@@ -2,21 +2,12 @@
 '@backstage/create-app': patch
 ---
 
-Migrated the app template use the new `withDefaults` to construct the `createApp` options, as not doing this has been deprecated and will need to be done in the future.
+Migrated the app template use the new `@backstage/app-defaults` for the `createApp` import, since the `createApp` exported by `@backstage/app-core-api` will be removed in the future.
 
 To migrate an existing application, make the following change to `packages/app/src/App.tsx`:
 
 ```diff
-+import { withDefaults } from '@backstage/core-components';
-
- // ...
-
--const app = createApp({
-+const app = createApp(withDefaults({
-   apis,
-   bindRoutes({ bind }) {
-     ...
-   },
--});
-+}));
+-import { createApp, FlatRoutes } from '@backstage/core-app-api';
++import { createApp } from '@backstage/app-defaults';
++import { FlatRoutes } from '@backstage/core-app-api';
 ```

.changeset/late-rice-sit.md

@@ -1,5 +0,0 @@
----
-'@backstage/core-components': patch
----
-
-Added a new `withDefaults` method that accepts a set of `AppOptions` and add the default components, themes and icons. It is intended to be used together with `createApp` from `@backstage/core-app-api` like this: `createApp(withDefaults({ ... }))`.

.changeset/twenty-swans-matter.md

@@ -2,14 +2,8 @@
 '@backstage/core-app-api': patch
 ---
 
-Deprecated the defaulting of the `components`, `icons` and `themes` options of `createApp`, meaning it will become required in the future. When not passing the required options a deprecation warning is currently logged, and they will become required in a future release.
+The `createApp` function from `@backstage/core-app-api` has been deprecated, with two new options being provided as a replacement.
 
-The keep using the default set of options, migrate to using `withDefaults` from `@backstage/core-components`:
+The first and most commonly used one is `createApp` from the new `@backstage/app-defaults` package, which behaves just like the existing `createApp`. In the future this method is likely to be expanded to add more APIs and other pieces into the default setup, for example the Utility APIs from `@backstage/integration-react`.
 
-```ts
-const app = createApp(
-  withDefaults({
-    // ...
-  }),
-);
-```
+The other option that we now provide is to use `createSpecializedApp` from `@backstage/core-app-api`. This is a more low-level API where you need to provide a full set of options, including your own `components`, `icons`, `defaultApis`, and `themes`. The `createSpecializedApp` way of creating an app is particularly useful if you are not using `@backstage/core-components` or MUI, as it allows you to avoid those dependencies completely.

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

@@ -25,30 +25,25 @@ import { entityPage } from './components/catalog/EntityPage';
 import { searchPage } from './components/search/SearchPage';
 import { Root } from './components/Root';
 
-import {
-  AlertDisplay,
-  withDefaults,
-  OAuthRequestDialog,
-} from '@backstage/core-components';
-import { createApp, FlatRoutes } from '@backstage/core-app-api';
+import { AlertDisplay, OAuthRequestDialog } from '@backstage/core-components';
+import { createApp } from '@backstage/app-defaults';
+import { FlatRoutes } from '@backstage/core-app-api';
 
-const app = createApp(
-  withDefaults({
-    apis,
-    bindRoutes({ bind }) {
-      bind(catalogPlugin.externalRoutes, {
-        createComponent: scaffolderPlugin.routes.root,
-        viewTechDoc: techdocsPlugin.routes.docRoot,
-      });
-      bind(apiDocsPlugin.externalRoutes, {
-        createComponent: scaffolderPlugin.routes.root,
-      });
-      bind(scaffolderPlugin.externalRoutes, {
-        registerComponent: catalogImportPlugin.routes.importPage,
-      });
-    },
-  }),
-);
+const app = createApp({
+  apis,
+  bindRoutes({ bind }) {
+    bind(catalogPlugin.externalRoutes, {
+      createComponent: scaffolderPlugin.routes.root,
+      viewTechDoc: techdocsPlugin.routes.docRoot,
+    });
+    bind(apiDocsPlugin.externalRoutes, {
+      createComponent: scaffolderPlugin.routes.root,
+    });
+    bind(scaffolderPlugin.externalRoutes, {
+      registerComponent: catalogImportPlugin.routes.importPage,
+    });
+  },
+});
 
 const AppProvider = app.getProvider();
 const AppRouter = app.getRouter();