Use the new :up migration testing rake task
In gitlab-org/gitlab!71111 (merged), we switched to gitlab:db:migration_testing:up
and gitlab:db:migration_testing:down
rake tasks, and an associated new directory structure. This MR switches to gitlab:db:migration_testing:up
in the testing pipeline, so that we can remove the old gitlab:db:migration_testing
rake task.
Relates to #18
Edited by Simon Tomlinson