Added reference to pypa/setuptools#4025 relating to pinning of GHA actions.

Author: jaraco

index.md

@@ -162,6 +162,7 @@ Features include:
 - run on late (and updated) platform versions
 - automated releases of tagged commits
 - [automatic merging of PRs](https://github.com/marketplace/actions/merge-pull-requests) (requires [protecting branches with required status checks](https://docs.github.com/en/free-pro-team@latest/github/administering-a-repository/enabling-required-status-checks), [not possible through API](https://github.bestrui.topmunity/t/set-all-status-checks-to-be-required-as-branch-protection-using-the-github-api/119493))
+- [unpinned actions](https://github.com/pypa/setuptools/issues/4025)
 
 
 ### Continuous Deployments