wrap numeric literals in quotes in gitlab-ci config

Why is this change being made?

When I onboarded a month or so ago, @laurenbarker told me GitLab Runner local installations were no longer working. I have been slowly working on larger and larger tasks and really wishing I had a local runner available to me.

This morning, @jgarc257 was looking for the same convenience. I gave it another shot this afternoon and finally figured out the right search term.

I was receiving the errors like this:

FATAL: invalid value for variable "GET_SOURCES_ATTEMPTS" 

But with different variables each time. So I Googled gitlab runner invalid value for variable and landed on this Gitlab issue about invalid integers.

As suggested in the thread, I wrapped the numeric values in quotes and my local runner started working again. I haven't tested it with the whole pipeline yet.

As I'm writing this, I see my pipeline on this MR is failing, so maybe this isn't quite the full solve yet. I wrapped two values further down in the file that I didn't do before, and perhaps that was the incorrect move. I'll try changing those back in a moment.

If that pipeline passes, I think this will fix local gitlab-runner builds for the repo.

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
• Assign this change to the correct DRI
  • If the changes relate to any part of the project other than updates to content and/or data files please make sure to ping @gl-static-site-editor in a comment for a review and merge. For example changes to .gitlab-ci.yml, JavaScript/CSS/Ruby code or the layout files. (this requirement has been removed pending identification of a new DRI for the handbook)