Blog post: Resolve "3 YAML tips for better pipelines - 2020-10-01"

Closes #8867 (closed)

Checklist for writer

• Link to issue added, and set to close when this MR is merged
• Due date and milestone (if applicable) added for the desired publish date
• Please add links to three related blog posts, GitLab issues, documentation or other related content so the reader can learn more at the bottom of the post. (We will take care of the formatting.)
• If time sensitive
  • Added ~"priority" label
  • Mentioned @rebecca to give her a heads up ASAP
• Blog post file formatted correctly, including any accompanying images
• All relevant frontmatter included
• Review app checked for any formatting issues
• Reviewed by fellow team member
• If approval before publishing is required
  • Any required internal or external approval for this blog post has been granted (please leave a comment with details)
• Assign to @rebecca for review

After the blog has been published:

• Share on your social media channels
  • Add ?utm_medium=social&utm_campaign=blog&utm_content=advocacy to the end of the blog URL when you share on social media, for data tracking. Your link should look like this:https://about.gitlab.com/blog/20xx/xx/xx/blog-title/?utm_medium=social&utm_campaign=blog&utm_content=advocacy
• After you've shared on your social media profiles, select one of the posts and link it in the #social_media_posts Slack channel for everyone to engage with your post. The GitLab social team may engage or even share your social media post to amplify the work.
• To learn more about how to use your own social media channels for GitLab, check out our team member social media guidelines here.