Update .gitlab-ci.yml to build to public folder with gitlab version 3.x
Change is needed so that build can happen to public folder. This is needed with gitbook version 3.2.0 as by default it builds to _book folder
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Change is needed so that build can happen to public folder. This is needed with gitbook version 3.2.0 as by default it builds to _book folder