[FEAT] Add release tag for major versions

[techsolo12]

Is this a new feature request?

• I have searched the existing issues

Wanted change

I would suggest that we add a release tag that enables a major version such as 27, 28 and so on in the docker hub.

Reason for change

With this change it is possible to stay on a major release when watchtower automatically updates the base images. It will always use only the latest version of a major release.
The reason for this is that the first versions of a major update on the nextcloud upstream usually have minor bugs. This means that the first releases can be waited for before the docker-compose is manually extended to the "new" major release.

Proposed code change

Unfortunately, I find programming very difficult and it's not my thing at all. I am already proud when I finish my shell scripts. Unfortunately I can't actively contribute to this change and have to rely on the help of the community.

[github-actions]

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[j0nnymoe]

Dupe of this: #361 Where it's already been discussed.

[j0nnymoe]

And to note about your watchtower comment, We do not support nor recommend any automatic updating tools for our containers. While yes you can get away with using them for some containers, Nextcloud is not one of those you can.