Pin GitHub Actions to full-length commit SHAs

[danfiedler-msft]

Summary

This PR pins GitHub Actions to full-length commit SHAs for improved security and reproducibility and adds a 7 day cooldown to Dependabot configuration for GitHub Actions. This work is described in more detail at https://aka.ms/action-pinning.

Why?

Pinning actions to commit SHAs prevents supply-chain attacks where a tag could be moved to point to malicious code. This is a recommended security best practice per the GitHub Actions security hardening guide.

This change mitigates the risk of tag retargeting to malicious code as seen in incidents like the tj-actions/changed-files action compromise or codfish/semantic-release-action compromise and improves the integrity and reproducibility of the CI/CD pipeline.

What changed?

Action pinning: Third-party action references in .github/workflows/ that used mutable tag-based references (e.g., actions/checkout@v4) have been updated to full-length commit SHAs with a version comment (e.g., actions/checkout@<sha> # v4) using the pinact tool. References that were already pinned to a SHA, or that used immutable release tags, were left unchanged.

Dependabot configuration: .github/dependabot.yml has been updated to ensure a github-actions package-ecosystem section is present with a cooldown configuration (default-days: 7). This groups Dependabot PRs for GitHub Actions and enforces a minimum 7-day cooldown between updates. If the file did not exist, it was created. If a github-actions section already existed, only the cooldown block was added or its default-days value was increased to 7 if it was lower. The 7-day cooldown provides a window for the community to detect and report compromised releases before they are automatically proposed as updates, reducing exposure to supply-chain attacks via newly published malicious versions.

Is this safe to merge?

Yes. The pinned SHAs correspond to the same commits that the existing tags pointed to. No behavioral changes are introduced. You can verify the pinned SHA value using the GitHub REST API (e.g., the commit hash for actions/checkout@v7 can be found in the sha property in the JSON response for GET https://api.github.com/repos/actions/checkout/commits/v7).

Additional Information

For more information, please see https://aka.ms/action-pinning

[Copilot]

Pull request overview

Updates GitHub Actions workflow files to keep already-SHA-pinned action references, while correcting/standardizing the inline version annotations to match the pinned commit tags (improving auditability and reproducibility without changing behavior).

Changes:

• Adjusted the PyPI publish action’s version comment in release.yml to reflect the actual v1.14.0 tag (and removed the inaccurate release/ prefix).
• Updated version comments in ci.yml for coverage commenting and artifact upload/download actions to reflect the specific tagged versions corresponding to the pinned SHAs.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
.github/workflows/release.yml	Normalizes the gh-action-pypi-publish pinned-SHA version comment to v1.14.0.
.github/workflows/ci.yml	Updates version comments for pinned-SHA actions to the specific tag versions (coverage comment + artifact upload/download).

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