All the docs indicate there is an overload constructor to allow you to connect using API Keys. I am using version v6.2.0 when I try `var transportWeb = new Web("This string is an API key");` I get a message cannot convert string to NetworkCredential. In v6.2.0 there does not seem to be a constructor for SendGrid.Web that takes the API key. I also checked the source code and confirmed that there is no constructor that for API Keys