Unity Package Manager compatible version of RevenantX/LiteNetLib.
As git packages are not yet supported in the Package Manager GUI you'll have to reference it yourself via manifest.json, located under <project path>/Packages/manifest.json.
Simply add this package as a new dependency using the syntax shown below.
"de.cryma.litenetlib": "https://github.com/Cryma/LiteNetLib.git"After restarting Unity the package can be used.
Important: If you use Assembly Definitions, don't forget to add de.cryma.litenetlib.Runtime as a reference.