Revert "Merge pull request #21 from Mook-as/out-force-tag"
Revert "Merge pull request #21 from Mook-as/out-force-tag"

This reverts commit 8c3605bec8c8ac897c606b3048812d44eb6f246e, reversing
changes made to 03556abe39ebd796aace96bcf0c524a8ca010d6f.

barthy1/docker-image-resource,barthy1/docker-image-resource,SillyMoo/docker-image-resource,SillyMoo/docker-image-resource,ggeorgiev/docker-image-resource,concourse/docker-image-resource,ggeorgiev/docker-image-resource,concourse/docker-image-resource