fix: remove greenkeeper-lockfile devDependency
fix: remove greenkeeper-lockfile devDependency

This was overlooked when merging updates from the project template.

Signed-off-by: Kevin Locke <ffb4761cba839470133bee36aeb139f58d7dbaa9@kevinlocke.name>

kevinoid/travis-status,kevinoid/travis-status,kevinoid/travis-status