Can't install with nuget

[LecksC]

Not sure why, but Install-Package Certes is failing. It works fine if I download the source and include it. To reproduce, create a .NET Core Web Application in VS2017 and run 'Install-Package Certes' in the Package Manager Console.

Install-Package : Package Certes 1.0.4.167 is not compatible with netcoreapp1.1 (.NETCoreApp,Version=v1.1). Package Certes 1.0.4.167 supports: net (.NETFramework,Version=v0.0)
At line:1 char:1
+ Install-Package Certes
+ ~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Install-Package], Exception
    + FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PackageManagement.PowerShellCmdlets.InstallPackageCommand
 
Install-Package : One or more packages are incompatible with .NETCoreApp,Version=v1.1.
At line:1 char:1
+ Install-Package Certes
+ ~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Install-Package], Exception
    + FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PackageManagement.PowerShellCmdlets.InstallPackageCommand
 
Install-Package : Package restore failed. Rolling back package changes for 'ASORSYNC2Server'.
At line:1 char:1
+ Install-Package Certes
+ ~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Install-Package], Exception
    + FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PackageManagement.PowerShellCmdlets.InstallPackageCommand

CSProj (default):

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp1.1</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <Folder Include="wwwroot\" />
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.0.0" />
    <PackageReference Include="Microsoft.AspNetCore" Version="1.1.1" />
  </ItemGroup>

</Project>