Update discovery.md

Signed-off-by: Gisela Torres <giselatb@outlook.com>

docs/integrations/github/discovery.md

@@ -26,27 +26,11 @@ package.
 yarn --cwd packages/backend add @backstage/plugin-catalog-backend-module-github
 ```
 
-And then add the entity provider to your catalog builder:
+And then update your backend by adding the following line:
 
-```ts title="packages/backend/src/plugins/catalog.ts"
-/* highlight-add-next-line */
-import { GithubEntityProvider } from '@backstage/plugin-catalog-backend-module-github';
-
-export default async function createPlugin(
-  env: PluginEnvironment,
-): Promise<Router> {
-  const builder = await CatalogBuilder.create(env);
-  /* highlight-add-start */
-  builder.addEntityProvider(
-    GithubEntityProvider.fromConfig(env.config, {
-      logger: env.logger,
-      scheduler: env.scheduler,
-    }),
-  );
-  /* highlight-add-end */
-
-  // ..
-}
+```ts title="packages/backend/src/index.ts"
+// github discovery
+backend.add(import('@backstage/plugin-catalog-backend-module-github/alpha'));
 ```
 
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