gitlab-ci: add condition to not build debian files if commit tag not equals koha release
gitlab-ci: add condition to not build debian files if commit tag not equals koha release

This is to be able to build new koha images without upping koha tag

digibib/koha-docker,digibib/koha-salt-docker,digibib/koha-salt-docker,digibib/koha-docker,digibib/koha-docker,digibib/koha-salt-docker,digibib/koha-docker,digibib/koha-salt-docker,digibib/koha-docker,digibib/koha-salt-docker,digibib/koha-docker