add link to prebuild example

Author: bahmutov

README.md

@@ -152,6 +152,8 @@ By default this plugin tests static site _after build_. But maybe you want to ru
 
 Parameters you can place into `preBuild` inputs: `start`, `wait-on`, `wait-on-timeout`, `spec`, `record`, `group`, and `tag`. If there is `preBuild` and `postBuild` testing with different tags, the first one wins :)
 
+See [netlify-plugin-prebuild-example](https://github.com/cypress-io/netlify-plugin-prebuild-example) repo
+
 ## Debugging
 
 Set environment variable `DEBUG=netlify-plugin-cypress` to see the debug logs. To see even more information, set `DEBUG=netlify-plugin-cypress,netlify-plugin-cypress:verbose`