Indicate correct Ruby version to install

[bewuethr]

Why:

Closes #17504

What's being changed:

Clarify the Ruby version to install to get Jekyll with the github-pages gem to build locally. This change is in a reusable snippet, used both in content/pages/setting-up-a-github-pages-site-with-jekyll/creating-a-github-pages-site-with-jekyll.md and content/pages/setting-up-a-github-pages-site-with-jekyll/testing-your-github-pages-site-locally-with-jekyll.md.

In both places, the current content is

and with the suggested change

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• For content changes, I have completed the self-review checklist.

Writer impact (This section is for GitHub staff members only):

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  • I have added the 'writer impact' label
  • I have added a description and/or a video demo of the changes below (e.g. a "before and after video")

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Content directory changes

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Source	Preview	Production	What Changed
content/pages/setting-up-a-github-pages-site-with-jekyll/creating-a-github-pages-site-with-jekyll.md	Modified	Original

[ramyaparimi]

@bewuethr
Thanks so much for opening a PR! I'll get this triaged for review ⚡

[guntrip]

Hi @bewuethr! 👋 In the time since you opened this, it looks like the github-pages gem now supports Ruby 3.x. I'd suggest opening an issue on the pages-gem repository if you're still having trouble.

As this seems resolved now, I'm going to close this PR and the associated issue. Thank you for taking the time to open this! ✨