Remove "up-for-grabs" label from PROCESS.md
https://gitlab.com/gitlab-com/www-gitlab-com/merge_requests/4080 got merged, so we have to update our documentation.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
https://gitlab.com/gitlab-com/www-gitlab-com/merge_requests/4080 got merged, so we have to update our documentation.