Using newer version of bops

[AskiaAHHill]

I want to use the newest version of bops as a dependency but it is failing testing for the 0.6 version of node. Would be ok to set the engine to be >=0.7 for this version of msgpack-js and for the rare person still running 0.6 or lower, they can use the older version.

[creationix]

I think that would be fine.