Add Metadata to Check

[jasonmfehr]

It we be very nice to have the git metadata added to the check script of this resource. If the metadata is in there, we can easily see what the next build will run without having to actually run the build or check github.

Thanks!

[vito]

This'll be done once concourse/rfcs#1 lands and we update the resource.

[jasonmfehr]

Thanks!