[GRASS-git] [OSGeo/grass] 66cbd4: Update docker/build-push-action action to v4

[renovate[bot]]

  Branch: refs/heads/renovate/docker-build-push-action-4.x
  Home:   https://github.com/OSGeo/grass
  Commit: 66cbd4e6047aa7f3fbeb6487166ff7c86661d712
      https://github.com/OSGeo/grass/commit/66cbd4e6047aa7f3fbeb6487166ff7c86661d712
  Author: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
  Date:   2023-01-30 (Mon, 30 Jan 2023)

  Changed paths:
    M .github/workflows/docker.yml

  Log Message:
  -----------
  Update docker/build-push-action action to v4