Fix 'liquibase-update' CI stage when triggered by a tag
Problem
As seen in the following pipeline, the CI job liquibase-update (triggered by tagging v5.11.0.0-1) is not able to work due to the lack of a corresponding docker image in
the gitlab registry:
This will probably not work as well for the job external-tape-formats.
Proposal
Add an optional branch/stage in the pipeline to generate these images, followed by the stage to run the tests liquibase-update and external-tape-formats.
Edited by Joao Afonso