Update Rubygems to 3.6.2 and Bundler to 2.6.2

[deivid-rodriguez]

What are you trying to accomplish?

Make sure new versions of Bundler & RubyGems play nice with Dependabot. These versions are the ones actually shipped with Ruby 3.4, so this should make Ruby 3.4 upgrade have less moving parts.

Anything you want to highlight for special attention from reviewers?

• Bundler 2.6.0 reverted the changes in the most recent 2.5.x that affected Dependabot, see Update Rubygems to 3.5.21 and Bundler to 2.5.21 #10746. We should now be fine in that regard at least.

• Bundler 2.6.1 caused an issue with tapioca. I proposed Support Bundler 2.6 Shopify/tapioca#2129 to tapioca to fix it. If that's merged and released, upgrading should fix the tapioca job.

• This PR supersedes Update Rubygems to 3.6.1 and Bundler to 2.6.1 #11164.

How will you know you've accomplished your goal?

CI passes.

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.

[deivid-rodriguez]

I pointed this PR to my tapioca PR just to prove the upstream fix and get CI green. Could be merged right away as is, and then point back to a tapioca release once the fix is included, or we can also wait for the fix to land and I'll update this PR accordingly.