Directory.Build.targets

<Project>
  <PropertyGroup>
    <RuntimeFrameworkVersion Condition=" '$(TargetFramework)' == 'netcoreapp2.1' ">$(MicrosoftNETCoreApp21PackageVersion)</RuntimeFrameworkVersion>
    <RuntimeFrameworkVersion Condition=" '$(TargetFramework)' == 'netcoreapp3.0' ">$(MicrosoftNETCoreAppPackageVersion)</RuntimeFrameworkVersion>
    <NETStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard2.0' ">$(NETStandardLibrary20PackageVersion)</NETStandardImplicitPackageVersion>
  </PropertyGroup>
</Project>