title: I can't use the new version on google cloud (app engine) without clearing cookies
body: <p>I have a React application that is running on google cloud (I am new to google cloud). My react version is "react": "16.8.3" (I think it is irrelevant but anyway). </p>
  
  <p>My problem is that when I have some developments I am running npm run build again and then I am using this command 'gc app deploy' to deploy the new version. After this when I run 'gc app browse' I can see and use my new version of app but when I go to real url I see it as the previous version. After I clear my cookies on browser (I have the same problem with the other browsers also) I can use the new version. </p>
  
  <p>I am using cloudflare and all the configurations that I made as following this article; <a href="https://medium.com/tech-tajawal/deploying-react-app-to-google-app-engine-a6ea0d5af132" rel="nofollow noreferrer">https://medium.com/tech-tajawal/deploying-react-app-to-google-app-engine-a6ea0d5af132</a> did not do any further configurations. I am using AWS for some other project and don't have this problem. Is there anyone with similar issue or anybody to help?</p>
  
  <p>Btw, my app.yaml as below;</p>
  
  <pre><code>runtime: nodejs
  env: flex
  manual_scaling:
    instances: 1
  resources:
    cpu: 1
    memory_gb: 4
    disk_size_gb: 10
  handlers:
  - url: /
    static_files: build/index.html
    upload: build/index.html
  - url: /
    static_dir: build
  </code></pre>
  
  <p>Have a good day!</p>