Pin github actions with ratchet - #276

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: docker/build-push-action@ca052bb54ab0790a636c9b5f226502c73d547a25, docker/login-action@465a07811f14bebb1938fbed4728c6a1ff8901fc, docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051, docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/