Update dep to remove warn about cross-spaw

[luanmuniz]

With this the following warn is fixed

npm WARN deprecated cross-spawn-async@2.2.4: cross-spawn no longer requires a build toolchain, use it instead!

[coveralls]

Coverage remained the same at 95.413% when pulling 33f0273 on luanmuniz:master into fec48cb on observing:master.

[3rd-Eden]

Error: In order to use spawnSync on node 0.10 or older, you must install spawn-sync

So it needs to have the spawn-sync module installed as well in order to not break backwards compatibility.

[luanmuniz]

Is there any interest in doing this after the TLS for 0.10 and 0.12 ends?

[3rd-Eden]

Well all that is needed is to add spawn-sync to the dependencies and it should just pass the tests again.

[coveralls]

Coverage remained the same at 95.413% when pulling 58a4511 on luanmuniz:master into fec48cb on observing:master.

[luanmuniz]

@3rd-Eden You are right, sorry. i was reading the name of this module and thinking on another. Just added the dependence.

[coveralls]

Coverage remained the same at 95.413% when pulling 69e8b0e on luanmuniz:master into fec48cb on observing:master.

[coveralls]

Coverage remained the same at 95.413% when pulling 69e8b0e on luanmuniz:master into fec48cb on observing:master.

[3rd-Eden]

Thanks for your contribution :)