This successfully deletes the atlantis lock and
allows a competing PR to plan, but doesn not delete
the actual plans, so a user can still apply after
the lock is discarded.
This will be investigated in a follow up commit
Also fixed the basic mark down rendering for the discard command
* If output is longer than 12 lines, wrap it in markdown folding for
GitLab and GitHub.
* Reformat the Terraform plan output so that the + and - lines show up
highlighted properly when using the diff syntax highlighting
GitLab allows repos to be nested under multiple subgroups,
for example owner/group/subgroup/subsubgroup/repo vs. owner/repo. This
change enables that functionality.
