Add a note about GitLab QA page objects validator to docs

qa/README.md

@@ -17,6 +17,17 @@ against any existing instance.
 1. Along with GitLab Docker Images we also build and publish GitLab QA images.
 1. GitLab QA project uses these images to execute integration tests.
 
+## Validating GitLab views / partials / selectors in merge requests
+
+We recently added a new CI job that is going to be triggered for every push
+event in CE and EE projects. The job is called `qa:selectors` and it will
+verify coupling between page objects implemented as a part of GitLab QA
+and corresponding views / partials / selectors in CE / EE.
+
+Whenever `qa:selectors` job fails in your merge request, you are supposed to
+fix [page objects](qa/page/README.md). You should also trigger end-to-end tests
+using `package-qa` manual action, to test if everything works fine.
+
 ## How can I use it?
 
 You can use GitLab QA to exercise tests on any live instance! For example, the