Fix a typo in GitLab 11.6 release post
Fixes a typo about .gitlab-ci.yml
in GitLab 11.6 release post.
Regression of ~"blog post" !17025 (merged)
Target URL: https://about.gitlab.com/2018/12/22/gitlab-11-6-released/
Similar fixes: gitlab-org/gitlab-ce!23963, gitlab-org/gitlab-ce!23964
Edited by Takuya Noguchi