chore: update Docker image publish workflow (#4847)

* Use official action to log in to Docker Hub
* Run using pinned ubuntu-20.04 environment

ci/steps/docker-buildx-push.sh

@@ -26,11 +26,6 @@ main() {
   # Download the release-packages artifact
   download_artifact release-packages ./release-packages
 
-  # Login to Docker
-  if [[ ${CI-} ]]; then
-    echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin
-  fi
-
   docker buildx bake -f ci/release-image/docker-bake.hcl --push
 }