fix(gae): fix linting issues

Author: hivanalejandro

appengine/building-an-app/build/test/server.test.js

@@ -25,4 +25,4 @@ describe('gae_build_web_server_app', () => {
   it('should be listening', async () => {
     await supertest(app).get('/').expect(200);
   });
-});
+});