Issue #3230856 by tedbow, kunal.sachdev: Update README with instructions for manual testing

README.md

 Automatic Updates
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+Warning the 8.x-2.x version of this module is still in development and should only be used development and testing.
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 ### Automatic Updates Initiative
 
 - Follow and read up on
   [Ideas queue - Automatic Updates initiative](https://www.drupal.org/project/ideas/issues/2940731)
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+### Manual Testing instructions:
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+1. Create a Drupal project via: `composer create-project drupal/recommended-project:9.2.5 test_updates_project`. Change `9.2.5` to the patch release before the most current version of Drupal. For instance, if the latest version of Drupal core is `9.2.8` then use `9.2.7`
+2. `cd test_updates_project`
+3. `composer require drupal/automatic_updates:2.x-dev`
+4. `cd web`
+5. Install Drupal: `php ./core/scripts/drupal quick-start standard`
+6. You should see a browser open and log you into the new Drupal site.
+7. Click "Extend" in the sidebar.
+8. Enable the "Automatic Updates" module.
+9. After you have installed the module at the top you should see an "Automatic Updates" tab at the top of the page.
+10. Click the "Automatic Updates" tab.
+11. You should see an update form with the next of Drupal core as the "Recommend Version". For instance if in step #1 you ran `composer create-project drupal/recommended-project:9.2.5 test_updates_project` and the latest version is `9.2.6` you will see `9.2.6` as the "Recommend Version".
+12. Click the "Download these updates" button.
+13. You should see a "Downloading updates" screen.
+14. Next you should see a "Ready to update" page.
+15. Click the "Continue" button at the bottom.
+16. You should see a "Apply updates" screen.
+17. You should be redirected to the "Available updates" page and see the message "Update Complete".
+18. You should see your version of core is up-to-date.
+19. 🎉