Updating dind image to `docker:stable-dind`

[jef]

I believe dind image was pinned to docker:18.09-dind because of this:

Starting in 18.09+, the dind variants of this image will automatically generate TLS certificates in the directory specified by the DOCKER_TLS_CERTDIR environment variable.

Source: Docker Hub

Without creating another volumeMount and volume for certs, we can ensure that 18.09+ doesn't run it's TLS cert script by overriding the entrypoint using command: ["dockerd"].

To disable this image behavior, simply override the container command or entrypoint to run dockerd directly (... docker:dind dockerd ... or ... --entrypoint dockerd docker:dind ...).

Source: Docker Hub

Although, I couldn't seem to get docker to run on port 2375 with this, but it avoided creating the certs and wasn't running on 2376. It seemed to just run off the sock and accept connections that way.

This could really be an issue with the docker image, but I just wanted to get some insight based on why the tag was pinned to docker:18.09-dind.

Thanks!