Docs: update DevOps stages
Requested by Mark P (https://gitlab.slack.com/archives/C16HYA2P5/p1540400685000100).
Update the stages https://docs.gitlab.com/ee/README.html#complete-devops-with-gitlab from:
To:
With all the content, ofc.
cc/ @gl-docsteam
Edited by Marcia Ramos