na hora de executar o comando install-package Entityframework -version 6.1.1 ele está dando um erro apresentando esta mensagem no console
Install-Package : Unable to find version '6.1.1' of package 'EntityFramework'.
At line:1 char:1
+ Install-Package EntityFramework -Version 6.1.1
+ CategoryInfo : NotSpecified: (:) [Install-Package], InvalidOperationException
+ FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand