Remove obsolete version element from docker compose files

[mpsantos]

Description

Removed the property 'version' from the docker compose files

Checklist:

• I've made sure that tests are updated accordingly (especially if adding or updating a template option)
• I've updated the documentation or confirm that my change doesn't require any updates

Rationale

The property 'version' now gives a warning that is deprecated. As this is an optional property, I think it's a good idea to remove it.

[browniebroke]

Thanks!