Update tag patterns

[Robinlovelace]

No description provided.

[Robinlovelace]

Hey @Nowosad and @jannes-m please could you take a look at the example above? I think we can now change all image types like this:

- ghcr.io/geocompx/docker:image_tag
+ ghcr.io/geocompx/image:tag

I lack time this week though, any help with this welcome, it's quite a big change so would like a couple of extra pairs of eyes on it if possible 🙏

[jannes-m]

I think you are right and that this change is overdue. The docker part in the image did not add much and we never had a version tag.
If we do that, we should also think about images releases that would then be used as tags. And we would have to change our documentation. At the top of my head I remember: gis chapter in our book and the basic qgisprocess vignette.

[Robinlovelace]

Thanks @jannes-m, this PR is designed to contain those updates to the docs you mention. If you could have a look at the readme and test out the new tags, particularly for the qgis image, that would be greatly appreciated.