Remove oddly formatted portion of example CI yaml from /gitlabcicdhandsonlab5.html.md

Why is this change being made?

A student in a training class I'm running noticed the extra markdown delimiter on line 40 of this file, and noted that the remaining contents of that example code block seemed confusing/repetitive compared to what precedes it. My guess it that the lines this merge request would remove were inadvertently copy-pasted into that section. If the actual contents is meant to be there, I'd be happy to revise my source branch so that it only removes line 40 (the markdown delimiter).

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
  • Copy/paste the Slack conversation to document it for later, or upload screenshots. Verify that no confidential data is added.
• Assign reviewers for this change to the correct DRI(s)
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the "Maintained by" section in on the page being edited.
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies.
• If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR.
  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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