Fix #47

In the past, we've observed intermittent network issues while communicating with dockerhub and this should help
alleviate that.

This fixes #42.

Perform automatic releases to GitHub

Closes #41

See merge request !43

hashworks authored Nov 01, 2020 and Sven-Hendrik Haase committed Nov 01, 2020

> Removing tags here will remove them from the "Supported" section on
> the Hub readme (and will prevent us from spending cycles rebuilding them
> on the official build servers), but the tags will still be available to
> users who want them.
> See https://github.com/docker-library/official-images#library-definition-files
> for more detail on this.

We have to do this in order to ensure that an updated .gitlab-ci.yml is actually available on every release.

We do a release every day so we end up with a lot of "release commits"
(noise) in the master branch, which we don't want.

Add base-devel tag

Closes #35

See merge request !39

We can simply construct it ourselves.