[CI] Drop EOL rubies

[dafyddcrosby]

Description

In today's community PR review we discussed how EOL Rubies have been broken on a variety of CI pipelines, gumming up efforts such as fully removing Chefstyle. After discussion with @tpowell-progress / @jaymzh we came up with removing EOL Rubies from repository CIs where there's no hard backwards-compatibility needs (eg mixlib-install).

Related Issue

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Chore (non-breaking change that does not add functionality or fix an issue)

Checklist:

• [ ] I have read the CONTRIBUTING document.
• [ ] I have run the pre-merge tests locally and they pass.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [ ] If Gemfile.lock has changed, I have used --conservative to do it and included the full output in the Description above.
• [ ] All new and existing tests passed.
• [X] All commits have been signed-off for the Developer Certificate of Origin.

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud