NuGet Package outdated since last improvements

Hello, the latest NuGet RSG.Promise v3.0.1 release was in July 26th, 2018. Since then it has been more then a year and a few improvements have occurred in the library, but no new NuGet releases yet. 

Is the NuGet being actively maintained?

Or should we now only get directly the source code? Could there be quicker to maintain alternatives to the NuGet package?