Reduce greenkeeper noise for devDependencies.
Reduce greenkeeper noise for devDependencies.

Greenkeeper has added support for using version ranges
and will only open PRs if new releases actually fail.

https://github.com/greenkeeperio/greenkeeper/issues/27#issuecomment-146212266

nodejs/new.nodejs.org,strawbrary/nodejs.org,wonderdogone/new.nodejs.org,phillipj/new.nodejs.org,boneskull/new.nodejs.org,abdelrahmansaeedhassan/yuri,yous/new.nodejs.org,rnsloan/new.nodejs.org,nodejs/new.nodejs.org,strawbrary/nodejs.org,yous/new.nodejs.org,matthewloring/new.nodejs.org,rnsloan/new.nodejs.org,marocchino/new.nodejs.org,boneskull/new.nodejs.org,abdelrahmansaeedhassan/yuri,phillipj/new.nodejs.org,wonderdogone/new.nodejs.org,matthewloring/new.nodejs.org,marocchino/new.nodejs.org