New article: Gitsign

[josecelano]

We can add an example repo and article or just add this as a resource.

• https://github.com/sigstore/gitsign
• https://www.chainguard.dev/unchained/keyless-git-commit-signing-with-gitsign-and-github-
• [ ] https://github.com/actions/runner/issues/667actions

cc @da2ce7