Current latest tag on Docker Hub is probably out-of-date

[white43]

Hi Ompragash,

We have run into similar issues related to the recent upgrades and downgrades of underlying base Docker images for this plugin. We found that latest tag was the reason why CI failed in our infrastructure (Cannot connect to the Docker daemon at unix:///var/run/docker.sock), while pinning 20.18.7 did solve our issues. What's weird is that the latest tag seems out-of-date on Docker Hub. Here is what I see on my side:

$ docker images | grep plugins
plugins/docker                                          20.18.7              11dafb688b26   42 hours ago    243MB
plugins/docker                                          latest               e3cb4d6d904b   5 days ago      243MB

$ docker pull plugins/docker:latest
latest: Pulling from plugins/docker
Digest: sha256:d73544e5ad5d6b0b065d82a25e9693128a2af3fc8983c5a0edb7b39607517113
Status: Image is up to date for plugins/docker:latest

$ docker pull plugins/docker:20.18.7
20.18.7: Pulling from plugins/docker
Digest: sha256:2074e91aa9f0bc8a7269dac9922e28a2cc0a0fa51a25ccfa749be53ed12a5504
Status: Image is up to date for plugins/docker:20.18.7

$ docker run --rm --entrypoint drone-docker plugins/docker:latest --version
docker plugin version 44157a2e

$ docker run --rm --entrypoint drone-docker plugins/docker:20.18.7 --version
docker plugin version 20.18.7

As we can see on the releases list (https://github.com/drone-plugins/drone-docker/releases?q=20.18.7&expanded=true), 20.18.7 points to the 44157a2 commit in this repository. So, I assume that plugins/docker:latest and plugins/docker:20.18.7 tags should be same docker image, but we see two different images with different digests. Not sure how it's happened, but the latest tag is probably out-of-date.