Dependencies should allow for up to version 4.x.x of puppetlabs-concat

I attempted to update puppetlabs-concat to the new 4.0.0 release, but noticed that puppetlabs-postgresql still requires concat < 3.0.0.

Unless there are any significant changes that prevent postgresql from extending the version range on concat to support 3.0.0 and 4.0.0, I'd like to see that bumped up.

This is an extremely trivial change, however. Not sure if it should be a bug, improvement, or task.