The PowerShell V6 release has been focused on several non-DSC specific features, but DSC benefits from their inclusion indirectly. No new built-in resources or cmdlets have been added.
While there hasn't been much new core to DSC, there has been a huge focus on making DSC cross-platform. Early support for Linux that was released around the first edition of this book has been fleshed out into fully featured support. Not only can DSC run on Linux, but it also has a complete set of built-in DSC resources. Underpinning this is a version of PowerShell that can run on Linux.