Move to ubuntu-slim

[MikeMcQuaid]

Let's try to see if these workers are faster and/or cheaper and still work.

[MikeMcQuaid]

Blocked on Homebrew/actions#770

[cho-m]

ubuntu-slim is a container so not sure if container-in-container will be supported. Maybe just try everything without container:? EDIT: or double check if any of these can run non-container.

[Copilot]

Pull request overview

This pull request systematically replaces the ubuntu-latest runner with ubuntu-slim across 14 GitHub Actions workflow files in an experimental attempt to evaluate whether slim runners provide better performance or cost efficiency while maintaining functionality.

Key Changes

• Replaced ubuntu-latest with ubuntu-slim runner type across all applicable workflow jobs
• Changes are consistent and uniform across all modified files
• No functional changes to workflow logic, only infrastructure changes

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.github/workflows/tests.yml	Updated syntax, vendored-gems, update-test (Linux), and analytics (Linux) jobs to use ubuntu-slim
.github/workflows/sync-default-branches.yml	Updated sync job to use ubuntu-slim
.github/workflows/stale-issues.yml	Updated both mark-stale and label-pr jobs to use ubuntu-slim
.github/workflows/sponsors-maintainers-man-completions.yml	Updated updates and issue jobs to use ubuntu-slim
.github/workflows/spdx.yml	Updated spdx and issue jobs to use ubuntu-slim
.github/workflows/sorbet.yml	Updated issue job to use ubuntu-slim
.github/workflows/sbom.yml	Updated sbom and issue jobs to use ubuntu-slim
.github/workflows/doctor.yml	Updated determine-runners job to use ubuntu-slim
.github/workflows/docs.yml	Updated docs, deploy, and issue jobs to use ubuntu-slim
.github/workflows/copilot-setup-steps.yml	Updated copilot-setup-steps job to use ubuntu-slim
.github/workflows/command-not-found-db-update.yml	Updated delete-old-versions job to use ubuntu-slim
.github/workflows/codeql-analysis.yml	Updated analyze job to use ubuntu-slim
.github/workflows/autogenerated-files.yml	Updated autogenerated job to use ubuntu-slim
.github/workflows/actionlint.yml	Updated upload_sarif job to use ubuntu-slim

Critical Issue Identified: The ubuntu-slim runner type is not a standard GitHub Actions hosted runner as of January 2025. All instances of this runner type should be verified to ensure it is either a newly introduced GitHub feature, a valid self-hosted runner label for this organization, or corrected if it's a typo. The workflows will fail if this runner type is not available.

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