Updated license to include .NET Foundation (#3189)
Updated license to include .NET Foundation (#3189)

Updated to include .NET Foundation, modified to follow Apache guidance which links to license terms rather than listing inline (https://www.apache.org/licenses/LICENSE-2.0).
Silv3rcircl3/akka.net,simonlaroche/akka.net,Silv3rcircl3/akka.net,simonlaroche/akka.net