I just updated my NuGet Package Manager on my corporate machine. Ever since the update, I am unable to add any package. I tried to install WebActivator for instance and got the following error:

```
PM> Install-Package WebActivator
Install-Package : The ServicePointManager does not support proxies with the https scheme.
At line:1 char:16
+ Install-Package <<<<  WebActivator
    + CategoryInfo          : NotSpecified: (:) [Install-Package], NotSupportedException
    + FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand

```

How can I go about this?