* provider/gitlab: add `gitlab_deploy_key`
Here we extend the gitlab provider further by adding a `gitlab_deploy_key`
resource. This resource allows management of a projects deploy
keys.
* provider/gitlab: Do not test `gitlab_deploy_key` `can_push`
Here we remove the testing of the `can_push` attribute. This makes the
tests less comprehensive, but will allow them to work with the current
release of gitlab-ce.
This change is staged as a distinct commit so it can be easily
dropped/reverted once gitlab MR !11607 has reached a released state.
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11607
* provider/gitlab: Update docs for gitlab_deploy_key/can_push
Note that the can_push attribute of gitlab_deploy_key doesn't currently
work. This note can be removed once
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11607 is merged
and in general circulation.