Once we take the 2.1.1 CLI changes (https://github.com/dotnet/source-build/pull/598), change the toolset so that we build 2.1.1 with 2.1.0. This happens to fix https://github.com/dotnet/source-build/issues/599 "released 2.1.300 sdk prints it is a preview message" for 2.1.1.
