Installing Ruby: Update ruby version to latest stable release

[nbarnabee]

Because

The version cited in the lesson (3.4.2) is outdated, and no longer appears as an option when using the rbenv install --list command, which may cause confusion.

This PR

• Updates the Ruby version number from 3.4.2 to 3.4.3

Issue

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project curriculum contributing guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide

[JoshDevHub]

I'm down to do this, but there are a few other changes that should accompany this change.

1. We like to keep the main app at the same Ruby version as the curriculum. This allows us to point to the curriculum's lesson for install instructions. Currently the main app is at 3.4.2, so its version needs to be bumped.
2. Throughout the Ruby course, two repos are worked in that will need their Ruby version bumped along with this to maintain compatibility across the course. They are the custom_enumerable_project and the ruby_testing repo.

If you want to take these on, feel free to let me know. You'll have to fork and clone each of the repos, adjust the .ruby-version file located in the root of the project to use 3.4.3, run bundle install to ensure there are no dependency issues on the new version, and then make a PR with those changes.

If that's too much for you to deal with (and no judgment if so), then we can get others to take on that work. Just might be a bit before this PR gets approved and merged since we'd need that other stuff ready to go.

[nbarnabee]

I'm happy to take that on, thanks.

[JoshDevHub]

@nbarnabee Awesome! Feel free to submit PRs for each of those repos, and then make a comment here that links those PRs.

If you need any additional guidance on how to do that, don't hesitate to ask questions. I'll gladly offer any support you need.

[JoshDevHub]

Approved but not merging until other version bump PRs are ready to go.