Warnings relating to "Microsoft.DotNet.Watcher.Tools" when running Koans

[tombusby]

Upon build, and upon run, I get these warnings every time:

/usr/share/dotnet/sdk/2.1.302/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.ObsoleteReferences.targets(33,5): warning : The tool 'Microsoft.DotNet.Watcher.Tools' is now included in the .NET Core SDK. Information on resolving this warning is available at (https://aka.ms/dotnetclitools-in-box). [/home/tom/Documents/tutorials/fsharp/FSharpKoans/FSharpKoans/FSharpKoans.fsproj]
/usr/share/dotnet/sdk/2.1.302/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.ObsoleteReferences.targets(33,5): warning : The tool 'Microsoft.DotNet.Watcher.Tools' is now included in the .NET Core SDK. Information on resolving this warning is available at (https://aka.ms/dotnetclitools-in-box). [/home/tom/Documents/tutorials/fsharp/FSharpKoans/FSharpKoans/FSharpKoans.fsproj]

I'm running the latest dotnet SDK on linux btw.