Consider explicitly tagging images prior to uploading them to docker registry

[banagale]

It seems like best practice is to explicitly tag an image using :latest. This is currently missing from the workflow for web and nginx: https://github.com/testdrivenio/django-github-digitalocean/blob/master/.github/workflows/main.yml#L45

Tagging like this is done in other parts of the guide, so perhaps this is just an oversight.

I've seen an SO where someone suspects their images on Github container registry are not getting updated because they are not getting explicitly tagged. I can't say if that's the case or not, but I came across it while trying to diagnose for #20.

Regardless, it would be great if the guide detailed automatically tagging images using the short version of the image's git commit hash.

If helpful, I could craft a PR for this issue.