Added Apache-2.0 license to gemspec.
Added Apache-2.0 license to gemspec.

Signed-off-by: Julian C. Dunn <jdunn@chef.io>

Pull request: #763
Approved by: adamhjk

nathenharvey/habitat,rsertelon/habitat,nathenharvey/habitat,rsertelon/habitat,rsertelon/habitat,nathenharvey/habitat,habitat-sh/habitat,rsertelon/habitat,georgemarshall/habitat,georgemarshall/habitat,habitat-sh/habitat,habitat-sh/habitat,nathenharvey/habitat,georgemarshall/habitat,georgemarshall/habitat,georgemarshall/habitat,nathenharvey/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,georgemarshall/habitat,habitat-sh/habitat,georgemarshall/habitat,habitat-sh/habitat,nathenharvey/habitat,rsertelon/habitat,rsertelon/habitat,georgemarshall/habitat