docs: add updating OAuth scopes guide (#35287)

apps/docs/content/guides/integrations/build-a-supabase-integration/oauth-scopes.mdx

@@ -15,6 +15,8 @@ Scopes restrict access to the specific [Supabase Management API endpoints](/docs
 
 Scopes are set when you [create an OAuth app](/docs/guides/platform/oauth-apps/build-a-supabase-integration#create-an-oauth-app) in the Supabase Dashboard.
 
+You can update scopes of your OAuth app at any time, but existing OAuth app users will need to re-authorize your app via the [OAuth flow](/docs/guides/integrations/build-a-supabase-integration#implementing-the-oauth-20-flow) to apply the new scopes.
+
 ## Available scopes
 
 | Name             | Type    | Description                                                                                                                                                                                                                                                                            |